I don't think the issue is really about feet. It's about men, or people in general, who feel shame about themselves. When you feel shame it's difficult to be honest and open.

Instead of being honest with themselves about who they are what they desire the blame is transferred to the "taboo" nature of feet. It's much easier to say that people just won't understand your foot fetish than it is to go to your partner and have the courage to be yourself with them.