In my later years I learned that greater portion of my bullies were having it off with each other. Their tough guy veneer was to help them keep their secret by intimidating others who knew. I hope they die horrible deaths from unspeakable diseases from fooling around with their heads hanging in shame.
Some may appear to be homophobic in order to hide their own desires towards the same sex. They may be ashamed or feel like their feelings are wrong, so in order to feel better or right about themselves they project hate towards the issue. It's just one way of coping with how you feel whenever you believe what you are feeling is wrong.
As a bisexual man, I have seen and heard numerous experiences with homophobia. What I tend to find is the individuals most vocal about homosexually, tend to be living secret gay lives. Check out any adult book store video booth area and you will find nothing but closeted men, desperate for sex.