I think that may be a very valid observation. No matter how big the difference between males and females there are always going to be those males who are more effeminate than average. And given human nature those are going to be picked on or shuned by some.
And while there are women who would find those attractive, group think sets in and they tend get shunned by women too. Women seem to be particularly bad about the group think thing too. JLo could date the ugliest most effiminate guy and girls would be lining up behind her. What's that about?
But I also think a good portion of homosexual males are introduced to homosexual sex at an early age. One of the reasons I think that is because one of my best friends in the second grade (that would be 7-9yo) propositioned me and said that he and a cousin had done it and it felt good. I didn't know much about sex at that age, but I knew I didn't want any part of what he was proposing. And several other gays that I've talked to admit to having experiences at a very young age.
Human beings are very complicated and there is never just one answer, to anything.