It’s not as if I go around referring to myself as a “homosexual” all the time, but it’s not a slur. It’s basically a scientific classification. I don’t call myself a homo sapiens either, not because it’s pejorative, but because it’s so gosh darn technical and boring.
Homosexual is literally the combination of the Greek word for same (Homos) and sexual. Same sex…as in “Same Sex Marriage” or “attracted to the same sex”. It’s a literal explanation of the sexual orientation of gays and lesbians. They are sexually attracted to the same gender.
Heterosexual is a combination of the Greek for different or other (Heteros) and sexual. Different/Other sex, once again a literal explanation of a straight person’s sexual orientation, they are sexually attracted to the other gender.
Bisexual also comes from a combination of the Latin root for two (Bi) combined with sexual. Two sex, a (nearly) literally explanation of a bisexual’s orientation, they are sexually attracted to two genders.
It’s not a slur, as Media Matters has now somehow come to believe.