I think it’s generally a good idea to respond to folks as if they were a friend or family member. And, if you need to pull the ripcord and get out of a conversation that’s terribly frustrating, it means a lot to say something to the effect of “Thanks for the chat, but let’s agree to disagree before we devolve into pure name calling.”
Or something. I think it benefits the whole community to have a record of people disengaging when the conversation isn’t productive. Doesn’t matter why. Doesn’t matter if you think the other person is clearly, obviously being an asshole. Politely disengage and try to stop thinking about it (if thinking about it is unproductive and stressing you out.)