But then I remember I didn’t take their children away, hook them up to a machine
to extract food from them, or kill them. And that makes me feel like making fun
of carnists is not so bad.
What's your objective? Probably you make fun of them because of your own emotional needs. Yes, you'd like them to change, but if you were consciously coming up with a method to engender change, you probably wouldn't choose mocking and alienation. Teasing is more likely a way of protecting yourself and your feelings, and trying to carve out some social space for them to exist in. Which is valid.
The single best thing any vegan can do to make more vegans is to be a visible positive example.
I'm a pretty visible positive example I'd say. My objective is to provide reminders to reframe carnism as socially stigmatized. I think this mostly works because a lot of my friends are vegan, but there are a few "bros" who rationalize why they don't need to change.
You can not, and should not, strive to change people. People can only change themselves. I think what you add here is spot on, people want to mimic those they admire, so the best we can do is be a positive example. Of course, speak the truth, we must be kind and accountable. The result will also lead you to being the best version of yourself, so its a win for us too.
If I had even ONE realistic example of a vegan in my life, instead of just carnist projections of veganism, I might have reformed 20 or more years sooner than I did.