Isn’t that kind of the point of having open communities, so that you can decide what does and doesn’t belong in your community without some centralized censor coming in and deciding what is acceptable in your community unless it’s illegal or actively harmful?

If you have definitive sources that vegan cat food with the appropriate taurine supplements aren’t ok for normal healthy cats then you can make an argument that that’s animal abuse, but otherwise you’re just applying your own preconceptions to their community.