i agree with lode, i know this girl who's fucking STUNNING i mean stop a room stunning. However she's dumb as a box of rocks so she's most likely gotten by on her looks most of her life. Or take me for an example i've always thought of myself as average at best, thus i've worked on being smart, being funny (sort of) and just being fun to be around. To me those things are way more valuable than being hot. i think some of us are just more comfortable about our insecurities where some people go through great lenghts to hide them.
You can't say one group would be more insecure than the other. We all have varying degrees of insecurity.