Reddit's response about the actions they took against the subreddits (note: r/mildly interesting DID NOT encourage nsfw content and their suspensions and removal have been revoked by a diff admin)
That's more a prudish American culture thing than a reddit-specific thing. We went to see the latest Guardians movie over the weekend, in which they foleyed out the line "classy hoes" from No Sleep Till Brooklyn, and showed all sorts of violence, gory deaths, and lots of pretty fucking serious child abuse. And finally dropped the first f-bomb in any MCU movie, in the line "open the fucking door," which was said not in anger, but in exasperation.
America loves its violence, but don't you dare make any reference to anything close to sexuality.