Some people have mentioned that some people with foot fetishes have a habit of trying to get people they find attractive to talk about their feet which makes everyone uncomfortable, to the point that it’s kinda of the main reason I think a stigma has formed against it.

If I met someone who for some reason I suspected was into feet, I’d be a little wary until I felt they weren’t gonna be weird about people’s feet, but I think if i met a knee fetish person, I’d be so surprised they exist that i wouldn’t think about this aspect even though it’s just as likely.