I'm not gay myself and definetly don't hate gay people but, what I do think is that there are some gay haters (not all of them!) who maybe a bit gay themselfs.
Homophobia among young people is common. That means: someone who simply has a dislike, hate or fear of gay people. It'll mostly in boys who want to attach additional to their friends that they just are not gay. I called Laurens Buijs, he is an expert gender and sexuality at the University of Amsterdam.
"It's a kind of reflex. Homosexuality is seen as a threat to the male and / or heterosexual identity."
Boys often display homophobic behavior in a phase where their male identity yet not very firmly in their heads. "They therefore want to show that they are perfectly well able to take from their friends."
You do not necessarily have to be a little gay if you're homophobic, but it is possible. "Just look at the shooting of Orlando. The man there gave a massacre in a gay club, was rumored himself gay."