Uncomfortable with it? Well, free speech means free speech, so your friend has a right to feel uncomfortable with it. I disagree with the way he feels, but he has a right to feel that way.
Again, as long as he doesn't preach violence against gays or discriminate against them economically or politically, then there's no problem legally speaking. There's no law saying you have to be.... inclusive on a social level. But let me ask you something - would you have a problem with a poster that says "racism is a social disease"? I strongly believe it is a social disease (as in, it sets up barriers in society and prevents cohesion).
Let me ask you something - if someone said "I'm uncomfortable with the idea of a mixed-race marriage", what does that imply? That that person is a racist? I would think so! If someone doesn't like or is fearful of homosexual people, you have to ask them - why is that? Is it because they hate or are fearful of gay people? I would think so! And what does that make them? The only word I can think of is: BIGOTED!
Once again - if your friend doesn't publicly condemn homosexuals, acts violently against them or encourages discrimination on an economic or political level, then legally speaking, he's doing nothing wrong at all, and he has every right, I stress this, EVERY RIGHT to feel the way he does. It's only a social disease if it affects your actions in society. A privately held belief, so long as it is privately held and doesn't affect society, might be bigoted or distasteful or plain backwards, but it's not a social disease, as it doesn't affect society.
But the very minute he teaches his kids that gays are disgusting or sinful or inherently bad, then that is homophobic, as that affects society.
On a personal note: I would feel uncomfortable about any poster that displays human affection - it's just something I don't like to see. I have as many problems with that poster as I do with those victoria's secret ads on the bus. I know, men like Pretty Girls, but there's a time and a place for that - and those ads shouldn't be on buses. But I defend the right for those ads to exist. Remember, living in a world with free speech means that you have to deal with seeing things you don't like.
Your friend is more than welcome to put up a poster saying "GAY PEOPLE AREN'T SO GREAT AND I FEEL UNCOMFORTABLE AROUND THEM" No joke, you have the right to put up that poster right now. I mean, if the West Boro Baptist church can do it, so can your friend. If he doesn't like a message, he counter it with one of his own.
But he's still a bigot in my eyes.
