Excellent points and specific examples.
I think the more a site exists to have these kinds of contentious, complex dicussions – race, gender, gun control, cars vs. bicycles, whatever you can think of tends to be a flash point online – the more sophisticated their ruleset needs to be to handle it.
It’s often easier to say “look, we only discuss X here, if you want to discuss Y in depth, please do that elsewhere” if your site can have a narrow enough focus.
(As for your specific examples, I’d say “SJW” is immediately a pejorative label that should be disavowed as a matter of policy, and “bless your heart” is clearly condescending… but mostly not necessary to the discussion so it shouldn’t have been included. Stick to the already-quite-complex discussion without throwing in a bunch of extra language that can be “interpreted” differently. Stick to the facts, plain and simply as you can.)