Ignorant people piss me off more than anyone. FYL for sure.

"this barnacle"

I'm so sorry op that you must live in the same world as idiots like that--though the awesomeness of your calling him "this barnacle" has me distracted. That is a brilliant insult. Seriously. I bow to you. I snorted coffee up my nose I laughed so hard when I read it.

Here's an opportunity to educate him.

Well? Do they?

I'd use this as an opportunity to educate him - he might just be being a dick, which you'll work out pretty fast, but those people would usually go for a more outright and obvious insult. He might genuinely be incredibly uneducated (and before anyone questions how anyone could be SO uneducated, remember some people don;t believe in evolution.). You could shape his views about gay people, he might become more open-minded generally :)

kill yourself faggit

That sucks, OP. Some people are either flat out ignorant or complete dicks, just ignore him.

press charges.

Some people just aren't comfortable with gay people and don't know much about it. It's not ignorance, they just don't know how it works. Jeez, gay people demand to be accepted, and when people make an effort to try and accept them, they put them down.