Eh. I've known a lot of gay men who weren't effeminate at all. My personal experience is that while, yes, there are obviously effeminate guys who are gay, it's not pervasive in the subculture. Especially as gay folk have been more accepted into the mainstream. I certainly haven't noticed that bisexual guys are any less effeminate (nor moreso for that matter.)
I suppose it's just a matter of what an individual person likes. For some folks, having sex with a man who's at least to some degree hetrerosexual is a major turn on, because of the myth that hetero men are somehow more masculine than gay men.
Personally, while I'm not sexually attracted to effeminate men (I'm bi, and if I want femininity, personally, I'd rather seek it from women,) they can be one helluva lot of fun to be around and party with. And while I'm very glad we've a better handle on AIDS than we did years ago, I do miss the rollicking good times to be had watching and interacting with all the drag queens at the benefits.
As they learned at Stonewall: One underestimates a queen at one's peril. A drag queen, doubly so.