I remember quite clearly the time when practicing homosexuality was a criminal offense...then, homosexuality was not even in the backwaters, but underground.
Sexual intercourse between men has since been quite rightly de-criminalised and there is more tolerance of this behaviour,but I would certainly not describe practicing homosexuals as being in mainstream society.

For the last 25 years there has been a concerted attempt to by powerful pressure groups in the media, the entertainment industry and politics to have homosexuality accepted as just another lifestyle/behaviour, normal and safe, just part of life's rich tapestry......they might even have succeeded had it not been for the advent of hiv/aids and until this link is explained, homosexuals will always be outside of the mainstream.

There are other factors which make homosexuality a taboo in the minds of most heterosexual men.....perhaps women feel differently about these things.