I thought it was normal until the internet said otherwise.
They say it's the most common fetish. I've always guessed it was at least a good 10% of folks that like something to do with feet, with at least half of those too embarrassed to admit it. At least, that's what I tell myself to keep me from feeling like a super weirdo.
But yeah, I think the creepy factor with some feet people comes from the normalcy with which most people see feet. You'd never get away with asking a woman to show you her breasts or the like, but since feet are "harmless" some people feel emboldened to do so because they feel like there won't be any consequences.
It's really gross and dishonest, and I wish these folks could just keep it in.