It also seems like some of the people they want to "out" as being gay are not proven to be gay.
Straight Dope has an article about the whole "Lincoln was gay" thing. By the way, Log Cabin Republicans were not name after Abraham Lincoln's supposed homosexuality. The group was founded before that idea came out. Gays are trying to claim people to bolster their cause, which unfortunately might win (i.e. like the notion that "Jesus was black" gaining popular acceptance). Also, as others have said, we do not need to know people's sexual orientation because it is irrelevent.