This in 12x16 felt like another solid character moment, to me; not just the fact that Dean left, but that Sam stayed. I think it’s the same difference in attitude that prompts Dean to squash down and deny the things that worry him (or, the flipside of the same coin, to accept them with fatalistic helplessness) whereas Sam will stare steely-eyed and insistent into the face of his problems. (Of course, that can certainly be problematic too.)
The problem isn't that you've offended people, it's that you refuse to stop. People have asked you to stop, and instead of stopping you say "It's just a joke, chill." Because you're famous now, you can't talk like you do at home or in public cause no one here knows you. So, even if you don't mean it, apologize and watch your words. People take things from famous people way too seriously for no reason, but it's a problem they need to deal with.