I'm actually familiar with 4chan and lurked on it when I was underage at least daily. It was funny for the time.
I'm not sure where the idea comes from that the entire site's reputation is containerized inside /pol/ or any NSFW board. It's just misleading if you take 5 minutes to browse around (if you still can, anyway). The language and harassment used in ALL boards of any group of people or individual is disgusting.