Lotta people don't realize when you grow up with people, you have an affinity, a relationship you don't get with anyone else. After you're twenty years old, anyone you meet after that, it's different from the people you knew before.
Homophobia is like racism and anti-Semitism and other forms of bigotry in that it seeks to dehumanize a large group of people, to deny their humanity, their dignity and personhood.