I'm a vegan and I am pro-science in the practical sense of believing that the academic science communities are a useful and consistently true source of fact. I'm against this because I believe that controlling conduct on the basis of some conduct being "anti-science" is a post-hoc justification for policing norms. If conduct should be banned, let's be honest about the reason: it's because we (or more accurately, the moderators) believe the conduct is wrong or harmful or is otherwise distasteful and would rather it be gone. Hiding our motivations behind bureaucracy, procedure, or appeals to authority is a mechanism behind the centralization of social power.
If you, like me, want to be part of a community of individuals which agrees that harm against animals matters but this community doesn't, then the anarchist options are to leave and make or find a new one, or to get to work persuading people.
The top of a sandwich made of sliced bread is the same as the top side of the loaf.
A sandwich made of sliced bread has six sides. Two broad sides and four thin, crusted sides. Three of the crusted sides are straight and one is curvy. The curvy side is the top of the sandwich.