I agree. I can admire someone but that doesn't mean i have a crush on them. So, i'm not sure about the friend crushes. To each his own. I can think someone is "cool" for lack of a better term, and not have a crush. A crush imo, is a little more than saying i think you're cool. It means you feel a little more than that. Crush has an element of attraction to it i think. The feeling that if both cared enough (although it doesn't have to go in that direction) that there could, not should necessarily, be more.
If someone compliments you, you may respond differently depending on their motives. If they're simply being complimentary, you may think, that's cool or appreciate it for just that. But if they're complimenting you because of a crush, then it's a bit different. You may flattered, uncomfortable, or become even more interested if they spark your interest, and you feel the same.
