There is no environmental damage vegans do that nonvegans don't do as well, if not more. I say this as an omnivore. Your average person does not buy a lot of real leather, probably takes your average person several years even decades to buy a cow's worth. Even when vegans opt for plastic leather it's really not gonna be all that much.

There's no such thing as ethical consumption anymore. Just practices that reduce harm as much as feasibly possible. Veganism is overall great for the environment even if every vegan alternative isn't ideal for it. People who get all pissy about vegans are just mad that someone is acting "better" than them even if that isn't the attitude most vegans hold.