It's a common misconception that we remove quality answers for the hell of it. The vast, vast majority of removals are of one-liners, jokes, single-sentence answer attempts, and the not-exactly-occasional racist/sexist/othering quip; a smaller number are of somewhat longer answers that still don't pass muster (no, 3 sentences are unlikely to do if 1 won't); and a tiny number are of answers that meet our standards for depth and comprehensiveness but are missing crucial information or context, are not properly addressing the question, or get important things wrong. This comment I posted a while back gives a count of what the removed comments are actually like on a typical high-interest thread.

Also, we do not remove answers for a lack of pre-emptive sourcing. We have never required that an answer have sources cited from the get-go, only on request.

Edit: to the person who replied, thank you. Though I think someone who has just studied something a shit ton independently, especially if they hand over sources shouldn’t be deleted. I mean, if I got a historical degree in all the useless information I have knocked away in my scull that I could answer here and back up with sources - I’d be bankrupt and constantly in college and have like 10-15 degrees under my belt. I understand the derailment thing, but deleting things just appears sus,especially if people back up their answers with proof.

On the studied independently, I have no history degree, I'm not in the profession in any way shape or form. I am very open I am an amateur who just studied the three kingdoms era in my free time for a while.

I have not had posts deleted unless they fail to come up to the required standard. I even got flaired despite not having been bankrupted in college, you really don't need a history degree. If people post an answer with the required quality, they don't get deleted. There is nothing u/EnclavedMicrostate put says one is required to have anything you declared is needed.

Ask Historians maintains it's reputation for being a place of high quality answers by removing the one-liners (and the dodgy). There are other history reddits that allow one-liners and it works for them, this place fills a different niche that requires more from those answering, ensuring high quality answers.

I don't know how deleting one liners or bad answers that don't explain the answer properly is suspicious though

I’ll see a question I think is very interesting, see that there’s something like 5-15 responses, and when I check it every single one has been removed by a mod;

You know how every /r/AskReddit question for, say, "Teachers of Reddit" has a bunch of answers that open with "Not a teacher but..."? Consider that, but think that the people who come in to post those 5-15 responses to a question don't even have a relevant anecdote at all. Just because a question has 15 responses doesn't mean any of them are actually valid answers to the question.

even highly rated responses

Plenty of people drift in from /r/all, see a joke answer and upvote it. Or whatever.

Let's say you've just been playing the latest Assassins' Creed and you're curious: Did London in the 9th century actually look like what it does in the game? So you post the question here. Perhaps none of our early medieval flairs have seen it yet, or they're busy, or they're going through their sources to give you a worthwhile answer. In the meantime, you get five quick answers that say things like "Activision did their research for ACII so this one must be accurate, yeah" or "It was the CHRISTIAN DARK AGES and they tore down all the stone buildings and burned the books so NO" or "I saw somebody write about this on Quora once..." or "Ask your mum lol". The mum joke gets a few upvotes. But none of these are correct answers to your question so they all get removed.

Though I think someone who has just studied something a shit ton independently, especially if they hand over sources shouldn’t be deleted.

I'm not sure why you've added this in. We absolutely adore users who've independently studied topics - we have moderators (hi) who write about topics they haven't studied formally, even - and we don't remove answers from people without degrees. (We have actually gotten people angry at us when we remove their short answers because i HaVe A pHd In ThIs!) We only remove answers for quality-control purposes. And it sucks that that sometimes means we remove longer responses with sources listed, but bad sources do exist and people can sometimes even misinterpret good ones.