Regarding the "bumping" mechanism and its effect on "normies": isn't almost every forum like this? I can't think of a forum that doesn't shift threads with recent posts to the top. This isn't limited to 4chan or 8chan, so I think it's unfair to single them out as encouraging extreme views.
Regarding anonymity: perhaps anonymity has the opposite effect, allowing people to be more willing to have thoughtful discussions and change their minds, instead of having to stick to their guns for fear of losing face. Perhaps the freedom of anonymity allowed people to say what they always wanted to say but couldn't because they feared for their reputation.
All of which is not to say that 4chan and 8chan don't contain hate speech and other forms of expression deemed unacceptable in broader society. But perhaps the reason people say such things and talk in those ways isn't because of the forum itself, but because of the state that political discourse has devolved to these days. 4chan and 8chan are nothing more than fora at the end of the day; and if they're blocked, people will simply move to continue the conversation (just like they moved from 4chan to 8chan in the first place).
...so why is the right to live an absolute right? What does it mean for a right to be absolute? (e.g. if someone kills other people to save himself, was he entitled to do so on the basis of his right to live?) Who gets to decide what rights are absolute and what rights aren't? Whose responsibility is it to enforce these absolute rights (and thereby to impose corresponding obligations on other people)?
The logic of "absolute" rights requires an over-simplification that doesn't reflect how rights work in practice.