Fairly everything in this account—beginning with the claim that Islam is merely an "ideology"—either runs against the grain of historical consensus or is so phrased that it distorts historical facts beyond recognition. Islam is of course a religion (ideology has a connotation of false belief, whereas even skeptics of religion will accept that it involves an experiential dimension that the word ideology rarely suggests). Muhammad did not "come up with the concept of Islam." He had experiences that he described as revelations, urging him to preach a stricter, purer form of monotheism than he saw others practicing.

There's already been a fair amount of discussion on Middle Eastern religion before Muhammad. It was a mix of Christianities (some of which seemed to worship the three gods of the trinity, rather than a single Triune God), Judaisim, Zoroastrianism, and other paganisms. Many people practicing these religions were probably attracted to the purity of Muhammad's message—he was not simply "recruiting followers in secret to increase his manpower and political clout." Others, however, felt challenged by this new form of radical monotheism. This probably included priests and other leaders from the competing religions of the Middle East, whose congregations may in fact have been attracted to the stripped-down religious institutions and simpler message that makes up the core of Islam (e.g. Five Pillars rather than Ten Commandments; one text that was memorized rather than a bible full of seemingly conflicting books).

Muhammad did have a hard time in his local neighborhood. His story wasn't written down until sometime after events (approximately the same distance that separates Jesus from the Gospel of John), but there are hints in the Qu'ran itself which suggest that the picture we have is accurate, and the early adoption of the AH calendar, also indicates these events are historically factual. In 622, Muhammad and his followers fled persecution in Mecca, taking refuge in nearby Medina, but they eventually returned in force to Mecca in 630, and Muhammad died two years later in 632. The fighting involved was similar to the tribal warfare endemic to the region and was by no means the result of Islam's supposedly "authoritarian nature" (whatever that means; it seems like the author meant to support this claim with the "facts" that follow).

There was a period of conquest that followed during the century after Muhammad's death, but our verifiable details on this period are remarkably slim. We can put together a rough timeline of the Islamic conquests, culminating in an area ruled affiliated Islamic leaders stretching from Spain to East Africa to Central Asia. Byzantium contracted, but the empire survived until 1453. The Persian empire collapsed completely, but the elite Persian families eventually worked their way into the leadership of the new Caliphate. It is a gross oversimplifiction to say that "Islam destroyed both the Byzantine and Persian empires." It's hard to know how much of this warfare was actually "Islamic" and how much was caused by other factors, regardless of the religious tendencies of the leadership. Although jihad is a theme in the Qu'ran, it doesn't seem to have figured largely in accounts of the period until about 150-200 years after the events actually transpired.

Islam did eventually become the prevailing religion across a broad swath of territory, but this was a slow process. There seems to have been a fair amount of religious toleration, at least for Abrahamic monotheists (i.e. Christians and Jews), even during the period of the Crusades (which the Islamic elite saw as a sideshow to their more important wars for domination of the old caliphate). Christianity survived in both North Africa (e.g. the Copts) and in the Middle East (e.g. the Chaldeans, who have been largely displaced only in the last 10-15 years), as did Judaism. Most historians think that tax breaks for Muslims encouraged much of the conversion that did happen, although that's perhaps an overly-secular interpretation of events. In sum, the image an authoritarian ideology and forced conversions rings completely untrue with what we know about early Islam and the survival of Christian and Jewish communities.

I'm certainly not an expert on early Islam, but it's my understanding that the Arabs tended to prefer enticing Christians and Jews to convert by placing a jizya tax on them and seeing them as second class citizens. While this could be seen as forcing them to covert, I feel like it's a far cry from the "convert or die" methods employed in later years by Europeans during their religious crises (although I'm almost certain that some Arab commanders did put non-converts to the sword, but I'm not sure it's as widespread as this post claims).

This post also assumes that once a country became ruled by a Muslim leader, suddenly everyone became a Muslim, which was certainly not the case. Egypt, for example, wouldn't become predominantly Muslim until well into the Fatimid dynasty. I know nothing of how persecuted Jews and Christians were during this time, but I'm going to assume that "convert or die" methods were not used if Christianity was still the preominant religion for 400 years (and still maintains a very strong presence in Egypt today).

As for the Byzantine and Persian Empires, I can only say a few things. Islam did eventually bring out their end, but keep in mind that the Byzantine Empire lasted until 1453, and might have lasted longer had Christians not severely weakened it in the struggle between Catholicism and Greek Orthodoxy. The Persian Empire as well had really weak leadership by the time of the Arab conquest, and I believe there was a considerable amount of economic depression and civil war when the Arabs came. In fact, the while reason why the Arab Empire grew so quickly is through warfare, the Arabs also promised many a more stable life, and relative freedom from religious persecution (particularly towards the Jews. In the case of Spain, the Jews aided the Arabs in their conquest, something the Christians would remember when establishing the Spanish Inquisition).

The two things I would note about this are that the only sources that exist for these events are the Sira "heroic biography" accounts written by Muslims which have a strong religious component.

The precise veracity of these accounts is a hotly debated among scholars.

So what this commenter has done is take the basic outline of those accounts, radically re-interpret them in a negative light without any basis for doing so other than, apparently, what he views as common sense.

So to pick on some particular points here: "it's authoritarian nature seeks to dominate its host society into accepting its values." Nope. This is not well attested to in the historical record. Particularly not for the standards of the time. Neither Christian nor contemporary Islamic sources attest to this around the time of the conquests.

"he started recruiting followers in secret to increase his manpower and political clout." How do you know what his motivations were?

"Due to the continuation of the conflict, life became pretty inhospitable for him and his followers until they decided to move to another town to recuperate and build strength." Actually Muhammad was invited to Medina to resolve conflicts within the town. The result was the constitution of Medina, which is hardly an authoritarian document.

"they waged war against people from their old town until they achieved total victory." The sources say the exact opposite, that Mecca launched raids against Medina, so the commenter has literally no basis for assuming this.

"From there on, everyone in the town had to convert to Islam and the religion went on to conquer all of the Middle East." Nope. The coalition of Arab tribes that carried out the conquests was not, by any means, uniformly Muslim.

"Through the process of conquest, Islam destroyed both the Byzantine and Persian empires." The Byzantine Empire outlived the Arab conquests for about 800 years. The Persian Empire was incredibly frail to begin with. It collapsed and was destroyed pretty much the moment the Arabs invaded. Islam as such didn't have much to do with it.

Muhammad was born in a town where the government was ruled via consensus of upper class families (sort of like a house of lords in parliament).

Is this necessarily the good thing the original poster is framing it as? Mecca under the Quraysh was governed by the chiefs of the Qurayshi clans, but those who weren't members of the Quraysh tribe has absolutely no legal protections or recourse if they were abused.

For an extremely relevant example, once Muhammad's uncle, Abu Talib died, his uncle Abu Lahab rescinded the protection of the Banu Hashim clan to Muhammad. Suddenly, Muhammad had 0 rights at all in the city of Mecca and anyone could do whatever they wanted to him.

With the advent of Islam, unaffiliated persons suddenly had legal protection and recourse, as the tribal system of governance in the cities, at least, was replaced with a formal administrative one.

As /u/CptBuck noted, the Sira is the only source we have for the early life of Muhammad. I would add to his comments that the Sira provides a different timeline for the conversion of the Meccans. Muhammad started converting poor Meccans to Islam, was initially opposed by the leadership of the Quraysh, and was then offered sole leadership by the Quraysh when their opposition was unsuccessful. This was an offer he refused.

This commenter clearly is being polemical and likely doesn't regard the Sira as reliable. But they certainly have no other textual basis for most of their claims. If you're interested in an accessible version of the Sira in English, I would recommend Muhammad by Martin Lings. Lings isn't unbiased but his book is well-researched.

That comment is very inaccurate, its purposefully misinformative in order to give a negative erroneous viewpoint that Muhammed is a power hungry warmonger.