Okay,
you seriously cannot say it's not a sport unless you have tried it.
Before i became a cheerleader, i hated all cheerleaders and completely repelled the idea of even becoming one.
But anyways, here is my argument...
Reasons WHY Cheerleading is a sport:
1) We work just as hard as everyone else. We have long practices, we have to go to camp, we have to have very tight moves, we have to work out just as often (if not more) than most sports.
2) And yes, Cheer mostly is entertainment, but we have competition cheer too, and believe me, it's the hardest thing to win at.
3) Being a cheerleader is a commitment. If you have your whole dance down to a tee and someone gets sick or gets hurt then you have to re-do the entire dance. Sometimes you only have 5 minutes or so to do this.
I could really go on forever about why cheer is a sport, but i dont feel like typing the reasons. So you'll just have to trust me on this.
So before you say that cheer isn't a sport, ask around. Ask the cheerleaders. they will most definitely tell you otherwise.
Oh and you probably wont pick this as your best answer because it's not what you wanted to hear, but i wanted to state my case anyways.