It’s /r/science. Not every forum is an open mic night at the local bar. Even open mics have limits, for pity’s sake.
Say someone needs, for whatever personal reasons, to express their sense that the real problem with rape is how hard it can be for accused rapists. Does that necessarily belong at /r/earthporn? Or /r/askhistorians? More the therapist’s couch, I’d say.
Let’s set aside the obvious, unconscious, hateful pathos driving so many misogynistic troll brigades at Reddit. There are places meant for things other than every person’s every opinion. Some removals are curation, not censorship.