Honestly, the only thing I think of when I hear that is, "Wow, this guy is a complete idiot." Not bigotry, not they are a homophobe. I honestly think that the person who says that is a complete moron.
I'm not offended when someone say homo, gay, faggot, and stuff. Because it is true and I'm proud of who I am inside and out and I'm comfortable with being gay so there is no point for me to be offended. People who uses "No Homo" all the time aren't comfortable with their sexuality and want to ensure their peers that they're straight.
Never has offended me but it seems to me that most of the time when a guy says "no homo," very few people around had actually thought that but the second they say it it seems WAY more homo than it was to begin with. I know a guy who says it a whole lot and it reminds me of the character from orgazmo saying "I don't want to sound like a queer or nothing, but I'd like to make love to you dude."
So what I'm saying is no not offensive but kind of self-defeating.
It cracks me up. I say it myself all the time. The idea is basically hilarious: Straight guys are constantly reminding one another of the possibility of a gay meaning in everything they do. "No homo" clearly implies that many things in a straight guy's life are indeed "homo." Being a straight-acting gay man, I'm already aware of that--most of my hook-ups are "totally straight"--but it both amuses me and turns me the hell on to see the consciousness of it dawning in straight guys.
Doesn't offend me, but I think it's stupid. I think a person must be pretty insecure about their own sexuality that the feel the need to say it to make sure everyone else knows they're straight...
My friend said that for a good 2 years and then he finally came out and said he was gay. So ya....he was obviously insecure and felt a need to defend his reputation as a super hot "straight" guy. So much for that.