The restaurant I went to prepared the beans with pork fat and anyways refused to change anything about the menu. It wasn’t a genuine Mexican restaurant though since I live in Germany. The owners traveled to Mexico often though, got recipes from befriended Mexican chefs and imported some ingredients.
I know that because I used to go there often before I went vegan and was pretty sad that they went basically hostile when I carefully tried to order something vegan.
With carefully I mean without any preaching or judging or super complicated changes and custom wishes.
Could he a strongman