Homophobia is easily dismissed by homophobes with "I'm not afraid of gay people," where "afraid" is assumed to entail running the other way for reasons of physical or emotional safety. "I talk to gay people" and "I've never run away from a gay person" are often considered thorough falsification, as if white 19th century southerners could have proven their non-racism by talking to or not fleeing from black southerners. Think about that.
Homophobia is not the fear of being dominated by "a homosexual." Homophobia is the fear of being gay, which wouldn't be a problem, if not for the fact that being gay means being a woman, which again, wouldn't be a problem, if not for the buried-to-most assumption that women are the lowest form of anything.
Insinuate that a macho man is a girl and see how he reacts. "If you're not afraid of being a girl, put on this dress. Then let us talk about you the way that we talk about women. No, this is not a game of pretend. You are a woman. Are you OK with that?"
Homophobes are afraid of being women, who are worthless (in the fantasy!), which is why young men throw themselves on grenades. To be not worthless. Is there anything more masculine than throwing oneself on a grenade?
Women are considered worthless because the rejected son is worthless, and the son seeks to control women so as never to be rejected again. She who is worthless cannot reject him (even though she actually can, since it's a fantasy he doesn't quite believe) because her opinion is worthless. Thus men who spend their lives victimizing are reenacting a victimization. You reject me? You bitch! I will destroy you, or me.
Reasons boys feel rejected by mothers and act out with machismo may include the difficulties of parenting generally, the convenience of the less powerful mother as a rage target, the greater presence of the mother as opposed to the father (making her a greater focus of rage), the possible fragility of boy brains as opposed to girl brains, and the general systemic benefits available to boys (unavailable to girls) for acting like macho asshats.