Whats the point of this?
Think of olympic diving or gymnastics. These basically share all the same characteristics you mentioned but are generally considered sports.
You could say that the actual competition in bb'ing isn't a sport, because there is little physicallilty or skill involved, but the training involves a huge amount of both.
You could also say that steroids play a huge role in bb'ing and thus it isn't really a sport, its just who is taking the right concoction. But you'd be wrong, because this is how all SPORTS are.
IMO, if you just train like a bodybuilder, or are just training to get bigger/leaner, you aren't a bodybuilder or an athlete. You are a person that lifts weights and works out or trains. And if you compete in bodybuilding competitions then you are a bodybuilder. Its like if I were to join an MMA gym, and train LIKE an MMA fighter, but never actually fought someone. I couldn't go around saying im a fighter.
Although this has been beat to death and is pointless, you do bring up an interesting point about beauty pageants.
Really, IMO, the actual contest of bodybuilding is not very different than a beauty pageant. Sure you could argue that all the training and prep goes into it, but the same is true for a beauty pageant.
Training for a competition is very different, but is really not any different than any other person that is weight training and not competing. WHAT WOULD BE THE DEFINING LINE BETWEEN SOMEONE THAT WEIGHT TRAINS, AND SOMEONE THAT BODYBUILDS? Would it be that they train with higher volume, or that they are concerned with symmetry. There is no way of defining this.
So IMO, a bodybuilder is no more an athlete than the average person that trains to better themselves or a miss America contestant.