How am I supposed to try to convince you to stop eating meat if I have to set my morals aside and say insert opposing opinion

You have to do this basically every time you want to convince someone, occupying their position better than they can occupy it themselves and still coming out with the correct opinion is part of being empathetic and mature. There's not really any inherent or objective morality to whether or not raising and then killing your own chickens is good or not. Someone who's really invested in the concept of ownership as a specific right is really not going to care about your own moral code of infringing on the chicken's right to not be killed randomly. They're just going to say that it's their right to kill their chicken, and that's that. It obviously has to become bigger than that, you have to give alternatives, spell out why their ideological position doesn't really work out at scale, give out alternative perspectives, you have to be intellectually honest and give them ground when they push back.

If you just kind of, resorting to occupying your own position forever, and then calling out other people that violate that position, then you're just gonna be kind of blindly hitting other people for reasons that they don't fully understand, like what happens on the internet constantly. It's maybe more self-affirming to be someone else's ideological landmine, but I think it's probably harmful overall, because it's a selfish short-term gain that doesn't see the bigger picture. It prioritizes your own self-affirmation over someone else's ability to be emotionally vulnerable and open to new ideas. Your own morals should probably not preclude you from being nice to people that you see as bad or evil or dicks. But then that's just my two cents, I dunno.