I think the phenomenon you're observing here isn't really to do with health, but more of naturalness - or more specifically, perceived naturalness. Obviously a

I think the phenomenon you're observing here isn't really to do with health, but more of naturalness - or more specifically, perceived naturalness. Obviously a hamburger isn't literally natural, but it's made from beef and mostly nothing extra. An "Impossible Meat" burger was born out of a lab - researched, developed, tested, and finally manufactured. There's nothing "natural" about it, which can turn a lot of people off.