Answer:
Technically, homophobia is a phobia -- an unreasonable fear, in this case of homosexuals. Any phobia is "bad" in the sense that it hurts the person with the phobia. It can also cause that person to hurt others.
In casual use, "homophobia" is used to refer to anyone who is opposed to homosexuality for any reason. The most common reasons are fear and ignorance. Generally speaking, attitudes based on fear and ignorance are unhealthy for us.
No, homophobia isn't bad. Since the gay community starting protesting for equal rights to marriage in the US, people have changed from 100% homophobic to 100% non-homophobic. They now look down on those who are homophobic, but it's not bad to be homophobic. It's an opinion. Nobody's opinion is right or wrong, or better, or superior. Just because your opinion is the minority, doesn't mean it is wrong.
Gays don't want equal rights. They want more. Everyone is bullied, and they deal with it. Gays don't want to, do they cry until they get their own way. They want to be superior, not equal. They think everything in life is unfair to them because they're gay. They're wrong. Life is unfair to everyone, no matter their sexuality. It's not bad to dislike them, just how it's not bad to dislike an emo person. They cry so much about being bullied that people think it's wrong.