That would still leave only a very tiny percentage of straight women with gay friends. And I don’t count knowing a homosexual the same as being a friend.
We’ve got a little over 50% women in the population and about 2% gays, if each gay guy has 2 dozen female friends, which would really be a pretty small number, that covers the population.
Really it’s just a normal function of population spread. Most folks have at least 100 friends of at least casual nature, about half of them will be women, and a couple will probably be gay. That’s what happens when social animals socialize, we get a large number of friends and the demographic groups that our friends are part of become rather diverse.