This is a question that most people never really ask themselves while they motion through their workouts. But it is certainly worth to take a minute and reflect. Is it a sport? Hard to say, since you are just presenting a physique onstage, without any athletic elements.
Is it an art form? Closer, with the piece of art being you.
But most of all its a way of life. Once you have been sucked into the vortex of trainig, eating, and recovering, you realize that is indeed a life style. Here is one of my favorite lines is from Fort Minor "Remember the name":
"This is ten percent luck, twenty percent skill,
Fifteen percent concentrated power of will,
Five percent pleasure, fifty percent pain,
and a hundred percent reason to remember the name"
I believe this sums it up rather well; please note the fifty percent pain part. Bodybuilding is certainly not an easy endeavor, but rewarding in the end. Or as my training partner used to say: "I bodybuild, because you cannot do it!"
Stick with it