Insecurity comes in a variety of flavors and intensities, but the result is usually some form of lameness or douchebaggery. It's lame when people don't have any self confidence, and it's douchey when people are over-confident about something in order to cover up their insecurity.
The Gays are a stereotypically insecure bunch, which is part of the reason that I am not attracted to most of them. Girls are also frequently insecure. Both are often very transparent about how insecure they are with their bodies, the way they look, how they are being perceived, and your opinion of them. Girls have all this weird shit to live up to: looking and acting a certain way, jamming themselves into all these ridiculous clothes and shoes; being smart, but not "too smart," and being in a state of constant conflict with the guys they are dating. And gays sometimes feel inherently insecure simply because they are different, i.e not hetero. So, I'm not saying it's either groups' "fault" per se, I'm just saying it's lame and unattractive.
Homos can be very undeservingly vain. They'll have nice clothes and a nice haircut, and maybe even a nice body, and so they strut around embarrassingly—unaware of the irrelevancy of that shit. As I've said, clothes are not you, and I am perfectly capable of observing that the guy with a t-shirt on is much better looking and attractive than the gay bro that's all dressed up. Surprisingly, I don't get distracted by any folds of cloth or shiny objects they might be wearing.
Again, it's not that good looking guys don't look good in nice clothes. It's that the clothes barely fucking matter, and that trying really hard with that shit just makes you insecure.