I don't see how bodybuilders have anything to do with this discussion. Come to think of it, I don't understand bodybuilding at all; what's the point? And that's not a rhetorical or facetious question! If someone can explain the point of bodybuilding to me, please do. In my ignorance, I venture to suggest that bodybuilding would not make anyone a better cyclist.
It's a combination of building your strength and sculpting your body. Like many things, it's the challenge that draws people. I'm not a body builder but I used to work for one and I don't find it terribly mysterious. It's not really for me though.
One misconception is that body builders have 0 flexibility which isn't true, -at least not for the better ones. Maintaining range of motion and having strength through that range is very important. Cyclists can benefit tremendously from strength training though I don't think body builders make for the best cyclists.
Actually, if you put in a lot of miles on a bike you may need to do some form of weight bearing exercise to prevent bone loss (being it weight lifting, running, high impact aerobics, or whatever)