I definitely only mention it when relevant (making meal plans) because people's brains just shut down as soon as they hear vegan. Constantly the most idiotic arguments that they'd never use in other contexts.

I need to eat meat because of my protein-deficient Indigenous lion-ancestors and did you know there's no ethical consumption under capitalism so might as well maximize my unethical behaviors, also did you know only 100 companies produce 71% of emissions and they'd totally keep up that production even if consumption went down on a global scale?? Also I only ever eat meat from my uncle's ethical farm, who somehow also provides the meat for every fast food restaurant I go to, I'm basically vegetarian I only eat meat like twice a day!

I've started telling people "I'd rather not have a conversation about it because I've had this conversation hundreds of times, it's never productive and I usually end up rather upset". If they can't respect that, I figure they're not worth my time anyways.