If you were a bb pro would you refer to yourself as an athlete? I would prob. specify and say bodybuilder.
In my reviews, I try to refer to the competitors as "bodybuilders" and bodybuilding itself as "the bodybuilding industry". I just think that philosophically, a sport is an event where points can be scored in an objective way. No matter how you cut it, bodybuilding is subjective. Some things are "subjectively objective", i.e., the colour spectrum for example. But even though what distinguishes red from auburn from brown is subjective, once established, placement in that group is NOT subjective. For example, if we subjectively decide that six feet is "tall" you are then either "tall" or "not tall" based on that definition, and we can extend the definition further. So although the initial categorization is subjective, placement in or out of that category after they are established is not.
But how points are scored in bodybuilding is neither objective or subjectively objective - It is simply a subjective matter. Granted, I would not win the Mr. Olympia so presumably there is some degree of objectivity, but it is still subjective overall. Of course using this definition of a "sport", we would have to call ping pong a sport, so it would leave something to be desired.