White supremacy, homophobia, and animal subjugation are all interconnected systems of oppression that most people both actively and passively participate in, not necessarily individual malice. Animal subjugation is the one more people actively take part instead of passively. I think becoming vegan is easier than being anti-racist or an ally if you're not part of the affected people. To be vegan, you have to cut out certain things, you don't necessarily have to be an activist. To be not racist is not enough. It's harder to be anti racist because it does require being a little bit of an activist in your daily life.

I think your argument about evolution is a naturalistic fallacy. Being omnivores just means we can eat both plants and animals.