Homophobia stronger in unacknowledged gays.
That’s a bit of an oversimplification, but basically, people who have measurable same-sex attractions, but don’t acknowledge those, are likely to be more vehemently and/or violently hostile to gays than people who don’t have those attractions.
The observation that there’s an unusually high density of closeted gays involved in the most outspokenly hostile anti-gay stuff is not merely a confirmation bias; there’s an actual pattern there.