This coinage is offensive both as an etymological absurdity and as the crown jewel of political correctness. Is the afflicted person equally afraid of all things, or is he merely afraid of similarity? Why, neither—the phobia is triggered by the threat of exposure to an erotic attraction between people of the same sex (a disposition that was at one time conveniently described as homosexuality, but only until that term was vigilantly discarded along with the American Psychiatric Association's 1952 classification of the condition as a mental disorder).
When the word first appeared (in a 1969 issue of Screw magazine), a homophobe was understood to be a man who exhibited a disguised response to a blocked homosexual impulse. Today, it is widely applied to anyone who disapproves of gay people or their sexual practices, whether motivated by distorted religious doctrine, a senseless desire for conformity, or any other grounds. Even if the original psychopathological meaning is not intended, the term is at least suggestive of an irrational fear.
Bigotry is a deplorable thing in itself. Those who would deprive a harmless segment of the population of its humanity and dignity may be condemned without falsely characterizing their motives.