Eating meat requires a victim. You literally have to kill another being for it. You can’t deny this, because it’s a fact. And vegans do not want to participate in that. This isn’t complicated. You choose to participate in the victimization of animals when you are eating an animal that is grown and/or killed for your products. Doesn’t matter the circumstances, doesn’t matter how, why, when. The animal that is killed is a victim, doesn’t get much clearer than that.
You’re making it out to be black and white because a child can do this logic. But it’s not black and white, there are plenty of edge cases to discuss, and that’s literally what the vegan community is doing all the time with many proponents of many different opinions.
But we’re vegan because we accept this simple logic and wish to minimise it as much as possible. And food is the easiest, since our body doesn’t need it. Plenty of vegan solutions available for the many cases where animals are victims. No need for leather, no need for wool, no need for honey, etc. Minimising animal victims is the goal here. It can never be zero, it can never be black and white.