That's the problem when a site or fandom grows too big, the normies and redditors get in.
The ''live and let live'' principle is more or less universal among Japanese otaku and largely dominant among western fans as well if you look outside heavily moderated echochambers. But ever so often you see these people act as if not only should everyone adapt their preferences to fit their particular fancies, but it's pretty much their god-given right to have their will imposed on others. Let's just say that looking at their kinda mentality gives you a very good idea where they stand when it comes to individual rights.
The thing that manga and doujinshi (but sadly not anime due to higher production costs) has western media beat is the huge diversity in the medium which can only really be matched by regular books, but where it can still fulfill a niche due to being consumed in a different fashion. Whatever setting you could think up that you'd want to read, chances are there's a manga or doujin that has it or is at the very least close to it. But due to these people's lack of critical thinking they simply can't process that free speech the lack of regulation within the medium is the reason that their particular niches are so well catered to in the first place. They don't think, they simply feel.
As for lolicon in particular I'd like to remind everyone that these people aren't interested in helping children, since in that case they'd just look at the facts and put their focus where it's most needed. This picture explains it pretty well
It's all just about the mindset that everyone and everything centers around them so if they dislike something then it shouldn't exist, and using various scapegoat and appeals to emotion to try to justify their childish behavior.
