There are several degrees of homophobia, honestly.
Me, I AM a slight bit homophobic, because of an event in my past, that I wont say here again. That being said, I am totally okay with gay people. My father is gay, my brother is gay, one of my best friends is gay, one of my supervisors is gay, and I don't have a problem with them as people. Their sexual orientation has nothing to do with it.
However, I've been kicked out of a club once for punching a guy in the face. I was there with my brother and his boyfriend, and I was sitting with one of our female friends, and this guy comes up and starts hitting on me. Okay, I told him sorry, I'm straight. That didn't stop him from hitting on me, I told him, I'm taken. Nothing, he started touching my shoulder. At this point I told him to stop touching me or I was going to knock out his teeth (Boy, that escalated quickly). Still nothing, and by this time he had put his hand on my junk. I slugged him in the face...
I also would do the same thing you did if I saw two guys making out, (I would do the same thing if I saw a straight couple making out). Not because I'm homophobic, but because I don't find the male body attractive in any way.
My main point is being grossed out by homosexuality is okay, actively disrupting two consenting adults is not, and neither is causing someone physical, mental, or emotional harm just for being different.