I think it depends on the environment that you grew up in. I wasn't around naked guys when growing up, not even in the school gym. None of my friends got naked in front of me. The closest I ever get to a guy physically is a hug and handshake. I know that in some countries guys can be closer than this and it's perfectly acceptable, but that's the norm in those places.
I would be uncomfortable if one of my friends or even some random dude decided to get naked in front of me. My question is why? It's obviously done to draw attention, but what kind of attention are you looking for? You know the sort of culture you live in, so why would you do it expecting the guys around you to be comfortable with this?
People, especially women, love to call guys who are uncomfortable with this sort of thing "homophobes", but I personally don't care. I've never been offended by that label. I have nothing to prove by forcing myself to be comfortable with homosexuals and naked men. I don't have a problem with their lifestyle, I just choose not to be around it.
I could be a little biased though. In my efforts to be more "social" with all people, not just women, I've had a few encounters with gay guys thinking I was attracted to them, of course I had no idea these guys were gay, at least they didn't act feminine in any obvious way. Talk about awkward. After a few incidents it made me a bit paranoid about guys I don't know who engage me in fluff talk. I tell you what, there are a lot more homosexuals out there than I ever realized.
ZenGodMod said:
thus you men still need to get comfortable with your sexuality. once you do that you would lose that discomfort or lust. see beyond just parts. and see the person beyond their physical level.
Of what benefit is this to a guy? Why do I as a straight guy, need to be comfortable with seeing another guy rip his clothes of at a party? Especially if he isn't getting some special attention from a woman.
I can see all those things you mentioned perfectly fine with clothes on.