Mostly it’s that I don’t have any physical attraction to them, but once in a while (about twice a year if I’m on a lot of dating sites, or once every few years if I’m not), I’ll meet someone I actually think is good looking (a hint here is that I find most celebrities physically unattractive, apparently my sex drive is picky but I couldn’t tell you why – although I DO have a high sex drive…). I find the vast, vast, vast majority of men unattractive.
