Earlier quoted context omitted.
Eh, even with the lengths this comment went to present a working framing I still don't accept it. Either cannibalism is so objectionable that I'd refuse to patronize a restaurant that served human flesh, or I'd probably not mind them being cooked side-by-side. That might be a bigger things for vegans, by buying even vegetarian stuff from burger king you're supporting a company that financially motivates a lot of acti…
I'm struggling to think of suitable analogue that would work for someone who eats meat. If you have a better suggestion ill go with that. You're trying to bring logic into a moral decision. While I agree that that's the way I would approach it, it isn't the only way to approach it. As I said I'm a meat eater so I don't follow all the logical steps to being vegan, but that logical step I do understand.
Cooking the burger in beef/pork fat would likely be noticeable, but that is pretty trivial to avoid and _usually_ grills are crudely scraped down between different grillings, that will remove everything but trace amounts.