Such a strange attitude, and maybe people today won't recognize it so much, but it used to be pretty common!
That was often a sort of narrative when I was coming out in my youth. I often found myself up against ingrained attitudes that gay men found themselves strongly attracted to straight men and would try to seduce straight men.
You see that less today, because I think people are more sophisticated even if they remain homophobic in many senses.
But, wow, your story is certainly an extreme, crystallized example!