Blame the fundamentally false understanding of homosexuality that was nonetheless required to justify marriage equality.

In mammals, "gay" male behaviors are displays of dominance. They're simple means of organizing mate access hierarchies, which are never actually supplemented with genuine homosexual preference. Humans need something 99% of males will do in a captive single sex environment to be an immutable identity because males have a deep psychosexual womb envy fixation on being the desirable ones, getting to be the choosers, having actionable preferences, being in the position to reject, selecting instead of scavenging, etc.

The entirety of 20th century sexology amounted to trying to construct and maintain the clay colossus of immutable, non-malleable, hard-coded gay or straight male, because the alternative is admitting that the concept of sexual orientation cannot apply to something that isn't designed to be the picker.