Laser pointers: cruel or no?

I just spent half an hour watching the cats chase around a laser pointer. I haven't figured out if this is cruel or not yet. On the one hand, they go nuts for that little red dot. They run their little hearts out and jump on the walls chasing after it -- then they stalk it stealthily and pounce upon it. But it just seems so cruel that they never get to catch the red dot.

I seriously can't decide if I should not use the laser pointer because it's mean -- or if I should use it more because they love it so much. Is it any worse than them watching birds outside the window? It's certainly not worse than those DVDs and TV shows for cats. Any opinions on this out there?

Also, once I get my W2's, I'm going to get Tabitha spayed. I have to prove that I'm poor and then I give this charity a 10 dollar co-pay and they'll set everything up with the doctors office and then call me and tell me when her appointment is. They're gonna give her all her shots and spay her and not ask me for a dime. Isn't that awesome? Erin and Matt found it for me. Of course now that the time has come (almost), I'm worried. What if she gets sick or dies? Or what if she just doesn't react well to it and becomes a different cat -- she's already still skittish. She was a stray for goodness sakes!

And here's the thing: I know that spaying and neutering is for the greater good -- all these stray kittens are breaking my heart and the solution is to spay them and prevent the populations from growing -- I get that. But on the other hand, you're changing them -- you're messing with their hormones and making them more docile because it's better for you. And that seems so wrong some how... I'm putting her through unnecessary pain and trauma and risk of death. And that makes me feel so guilty. I'm afraid she's going to hate me forever for it. Would she rather still be a stray? Sure, as far as we believe, our pets have a great life -- food, couches, toys -- but then Jack runs out the door every time he gets the chance. They want to be outside running around and stalking the birds in the trees. That's their nature. Is it cruel to keep them in the first place? They're not like dogs...