FWIW, I’m not a vegan anymore, but I’d agree that any attempt to “minimize total suffering” would have to include not eating meat, ceteris paribus. So anyone who claims to have that goal but still eats meat is either a liar, or suffering from some sort of “intra-self disagreement”, or they believe ceteris is not paribus (e.g. “eating meat somehow lets me work harder on saving the world”), or they’re uninformed. (Or something else.)
Or they’re just satisficing rather than maximizing.
Or they’re just satisficing rather than maximizing.