A lot of the problems came about when sites began mandating "Real Names". People began to assume that online is somehow analogous to real life (it isn't). Combined with the nonsense claim that "hateful/rude/unpleasant speech and violence are the same", we're hurtling down a dangerous path.
This "safe" language is the normal Orwellian thin-end-of-the-wedge nonsense; Rude/Unpleasant/Hateful Speech, contrary to all the hand-wavy claims, simply isn't the same as violence.
Who is welcome? Anybody with a computer and an ISP. Note that everybody from white supremacists to the most Left of Left-leaning SJW have a voice.