Why did the top comment (which had several hundred upvotes and had been up for hours) get removed without explanation? There was a lot of discussion going on - what's the explanation for removing all of it?

I generally appreciate the highly moderated nature of this sub but it would good to get reasoning for actions like this.

While you wait, please check out this older answer by /u/talondearg, which covers the subject and also links to a few other answers for further depth.

Yes this is true, but depends on what your metric for a "new religion" is. For example, if you define a religion as a set of codified texts and practices, then yea the argument flies that both Judaism and Christianity as they are today are offshoots of a Levant religion that had become monotheistic only a few centuries before. In fact if you use this metric, there is no long thousands of years of Judaism and Christianity, but rather epochs of a broad church abrahamic theology:

The 'Apiru people.

Also known as the Habiru, the 'Apiru is likely the origin word for things like "Hebrew". In Hebrew itself, you say Hebrew as "Ibri". They appear to be the same people as the invading Hyksos people in Egypt, as Shasu of YHW is described as being from their lands and is at the tale end of the Hyksos era. These words for these people all roughly translate to "dusty" and "foreigner" and "shepherds". They're desert nomads, more or less.

Their practices do not seem monotheistic at this time. There is only one or a few "Yahwehist" factions arguing their God is the best. Their identity is by tribes and there is no unified organization among them. The few that can write appear to use a Phoenician type script which some movies like The Ten Commandments used to try to be historically accurate, but these are later versions of it. What they used was at least partially hieroglyphic.

Sources:

Universty of California article by Dr. Charles Wallis

Gary A. Rendsburg, Rutger Uni's The Early History of Israel

Following this period, the various tribes appear to have came together and formed a state. The Yahwehist faction appears to have gotten more influence initially, but fallen from total power. I'll skip this part as most of these factions got wiped out during the Babylonian Exile.

Following the exile, this Abrahamic religion entered a new epoch. A new alphabet was adopted, the Hebrew alphabet we know today. However the scriptures themselves were in Greek, to allow universal use in the Mediterranean. This was a point of contention for some who felt they were becoming too greek. It wad divided between four, possibly more, factions:

• The Pharisees, who were legal purists and probably the group responsible for putting the scriptures to a codified greek text.
• The Saudacees, who wanted to make Judaism more in line with Greek philosophy and theology.
• The Essenes, who were radical purists. They tended to write in the old pre-exile alphabet.
• The Zealots, who were further radicalized purists who took up arms.

Jesus himself, in my opinion, seems to show the most influence from the Essenes, but appears to have been educated as a pharisee, albeit not a formal member.

There are a lot of similarities between Essene writing and early Christian writing. Take, for example, this passage from Hannock, aka Enoch:

At that hour, that Son of Man was given a name, in the presence of YHWH of armies, the Before Time; even before the creation of the sun and the moon, before the creation of the stars, He was given a name in the presence of YHWH of armies. He will become a staff for the righteous ones in order that they may lean on Him and not fall. He is the Light of the gentiles and He will become the hope of those who are sick in their hearts. All those who dwell upon the earth shall fall and worship before Him; they shall magnify, bless, and sing the name of YHWH of armies. For this purpose He became the Chosen One; He was concealed in the presence of YHWH of armies prior to the creation of the world, and for eternity. And He has revealed the wisdom of YHWH of armies to the righteous and the dedicated ones, for He has preserved the portion of the righteous because they have hated and despised this world of oppression together with all its ways of life and its habits in the name of YHWH of Armies; and because they will be saved in His Name and it is His good pleasure that they have life.

source, I adjusted some words to modern english as this translation is nearly a century old.

In this we can almost see hints of the trinity idea starting to form, where the Messiah is hidden away, one with God. Co-eternal, etc etc. Essene writing appears to have laid the foundations for Christianity to grow on. When Enoch was written is unclear, however. Possible a century before Jesus, possible in the same century as Jesus. But very clearly in alignment with Christian theology more so than Rabbinical Theology.

Following the destruction of the temple, Rabbinical Judaism formed from the Saudacees and Pharisees. They finally put the text to Hebrew, and that is why our oldest Hebrew Old Testament sources are younger than our oldest Greek Old Testament Sources. This all changed with the Dead Sea Scrolls, of course. But it is very important to remember that at the time of Jesus, the scriptures were primarily in Greek.

So from this you might say, yes sure, Rabbinical Judaism and Christianity are about the same age, having been offshoots of those four factions of 2nd temple Judaism.

I would strongly encourage you to read Essene writings. It does seem that Christianity is its child and the result of it, while Pharisee and Saudacee Judaism are the parents of rabbinical Judaism.

Hope this helps!

A few sources on the Factions too!:

The Jewish Library

Dr James Tabor's article on UNC Charlotte

-Edits are for spelling

This was previously posted on another subreddit to which this post crossposted:

I am not sure what the author of the OP had seen, as what is there appears to be from two sources:

1. Theories about the development of Jewish Gnosticism after the first Judean war (66-73 CE), first proposed by Moritz Freidlander and most recently pursued by Birger A. Pearson. I first became aware of it in Gnosticism, Judaism, and Egyptian Christianity (Fortress Press, 1990).

In this scenario, Judean Gnostics (minim) developed out of the deep disillusionment of some Judean sages over the aftermath of the failed rebellion, reinterpreting their national god as a creator god who was ignorant of his origins and of the higher realms of existence. There is a certain connection to concepts characteristic of middle Platonism (Platonic philosophy as it existed in 1st century CE, which is similar to the philosophy of Philo of Alexandria). This was wedded with a divine redeemer myth that might have predated the evolution of the Judean Gnostic myth, but was not derived from Genesis like the Creator god idea was.

In a way, Christianity as we know it was a twin sister development from the same disillusionment after the defeat of the Judean rebellion, except here, the God of the Judeans was preserved as the supreme god, only his favored people (the Judean people) were rejected for getting things so wrong, and the promises made to them were transferred to gentile God-fearers through a mechanism that is similar to the Gnostic divine redeemer myth.

2. The second idea I see present in the OP are theories that the NT Jesus myths developed from earlier myths, but reinterpreted to make the mythical characters into one real-life man, Jesus. I believe this was first proposed by W. Benjamin Smith in his collection of essays in German on the origin of Christianity, Der vorchristliche Jesus, nebst weiteren Vorstudien zur Entstehungsgeschichte des Urchristentums (Mit einem Vorworte von P. W. Schmiedel Giessen: A. Zöpelmann, 1906).

Unfortunately I do not read German. But there is a good English review of Smith's book by Arthur O. Lovejoy in The Monist, Vol. 18-4 (Oct., 1908, pp. 597-609). He describes it as follows:

What we know as primitive Christianity, Dr. Smith contends, was the product of a vast and slow syncretism. The more fundamental and distinctive elements in it were derived from Gnosticism of which movement, therefore, it was the child, and not, as has been supposed, the parent. The Christian faith of the second century emerged, through certain processes of fusion and modification, out of the doctrines of quasi-Gnostic sects that flourished in Syria at least a generation before the Christian era. The name of its reputed founder, Jesus Nazoraeus, was originally that of a divine being or Aeon reverenced by the sect of the Naassenes, and probably by others. The semi-human figure who is the hero of the Synoptic Gospels was evolved (chiefly as the result of the partial transformation of this Gnostic theosophy through its merging with Jewish Messianism) out of the celestial object of this primitive Jesus-cult. The resurrection-belief originated in a sort of etymological myth...; the doctrine of 'the raising-up of the Christ' at first related, not to the reappearance of a body once entombed, but to the divine legation and the final triumph of the heaven-descended Messiah. The ethical and religious content of the extant Gospels consists, not of the utterance of a great Teacher more or less diluted and corrupted by the inferior media through which they are transmitted, but of the ultimate deposit of the reflection and discussion of several generations of men profoundly stirred by one form of that movement of mysticism, otherworldliness and aspiration after inner regeneration, which was then sweeping over the entire Hellenistic world. The literary excellence and the moral profundity of many of the sayings and parables in the Gospels is the result, not of the inspiration of a single Master, but of the long social attrition through which they were sharpened and polished, and of the gradual process of spiritual selection of which they are the fit survivors.

The only common element between these is Gnosticism, and this seems to have been the primary interest of the author from which the author of the OP drew his/her inspiration. Reminds me of some of the thinking of Simone Pétrement in her book le Dieu séparé (1984, ET by Carol Harrison, A Separate God: The Christian Origins of Gnosticism also 1984).