Take a young bigot. Raised a bigot, born into a family of bigots, and brought up believing clear definitions of right and wrong, good and evil, salvation and sin.
Put young bigot out into the world. Now comes the choice...
a) Treat him with contempt, denigrate his beliefs, and take every opportunity to force him to change.
b) Treat him with personal respect, openly discuss his beliefs and your own, and give him every opportunity to see how other parts of the wide, wide world operate.
Now, which one is going to work?
Of course, if the young bigot is beating the crap out of someone, or defacing other people's property, or otherwise acting out his hatred, slam his ass in jail, because he's crossed the line.
When someone directs complete hatred towards you, just because you are different...that sucks. It's easiest to hate right back. And yes, I *do* know that feeling, although it probably isn't what you think.
Toss the hate and lack of respect back at them, and the fire just builds. Show them personal respect, and, as buymeaclue says, don't be a jerk. They may come around. Maybe not all the way to your point of view, but less hostile. And given time...who knows?