The pitch being made in this subthread was "I don't think Reddit should be able to censor lawful content and also claim protections under Section 230 of the Communications Decency Act."
So you lose liability protection if you censor lawful content.
So if you want to ban swearing, you become liable for your user's content. Which makes you a WIDE OPEN target for bad actors who could post whatever illegal content they want faster than you could moderate it.
I'm trying to illustrate why I think `cwhiz took an absurd position, and am not using the term "trolling" in general now. I've given a specific example of "legal content some communities might want to prohibit" as well as "illegal content that bad actors could use to get the owner of that site in trouble in this proposed world."