I see no problem with defending freedom of horrible people. Both from an ethical standpoint, and from a pragmatic standpoint (I would rather those people communicate in a way that has some visibility/oversight. You are not going to stop them, only push them underground; I think most would agree that would be a bad thing.)
Yes, and? If you actually believe in free speech, calling someone a Horrible Person is not a disguised argument for shutting them down.
4chan is full of really horrible people. Sometimes I am one of them. This doesn't mean they should be shut down by the government or something. However, it also doesn't mean they're Glorious Heroes Fighting For Righteousness.
Who is arguing that?
Now surely everyone is going to yell that they're just protecting their beloved web from censorship. However, since I never proposed censorship, that means most of them are arguing against the evil, censorious Congressman in their own heads, rather than against anything I actually said.
> oldfriend
Hey wait a minute ...
CENSORSHIP
Now, if you want to call it "the last bastion of freedom [to spread hate ideologies, post loli hentai, etc]", go ahead. However, be clear that you are defending the freedom to commit immoral acts.
4chan is the Mal Reynolds of the internet, not Luke Skywalker.