I can verify this.
I've been able to return banter in game, some of it vitriolic and would fall under 'slurs', but so long as it's passably light-hearted banter for the situation and you're not whining about the game, you won't be banned.
If your expectations for what get you banned are shaped only by what shills who want to feel superior by diving the reason for your ban (and conversely by assholes who say u dindu nuffin), you will be pleasantly surprised with what people don't care about.
You have to be exceedingly obnoxious for a significant number of the average players to flag you. It's not just a bunch of triggered snowflakes.