Even people that haven't gone a day in their adult lives without eating flesh and adamantly insist that they don't consider something a real meal unless a creature died or was abused for it can be taught to go a few days a week without killing something if you give them the kiddie gloves.

This has not been my experience. I'm glad it's been yours, that's neat, but the two committed carnists in my life are absolutely impossible to reason with and if they weren't my (divorced) parents' new partners, I would have long since cut them out of my life. I have never seen either of them eat a vegan meal. Even when there's plenty of delicious vegan food around (and they themselves have made some of it!), the two of them go out of their way to add meat or eggs to whatever normal thing the rest of us are eating. They're both "supportive" of my parents eating vegan, but they themselves absolutely refuse to do so, and all the kindness in the world won't make them budge.