Being chased out is hardly the same as being banned.
It's not just "don't post NSFW links", it's also "don't do anything illegal" -- and yes, there are things you can post that would count as illegal, especially if they're followed with or preceded by action. This is not a head-case rule, this is a live-in-america rule. So things like links to snuff films, child pornography, &c. would be illegal, marked as such or not.
So you can say things like "you sick fuck", but I wouldn't recommend saying things like "you go to hell and die", because that could be interpreted as a threat, and would raise a big ol' red flag.
Unless, of course, you're quoting South Park.