Delw, pull back into reality.
Keep in mind the issue is not whether or not they need to be on lakes at all, the issue is whether or not they belong in a National Park.
The NP's are a totally different deal. I dont have a problem with them on lakes outside the park. For the record, AZ has some of the best lake management I've seen with the no-wake zones set up near the banks for fishermen, like at Bartlett, Pleasant, Roosevelt, etc. (By the way, a couple weeks ago my buddy and I tore the bass up on Bartlett). Keeps fishermen near the shorelines and the jet skiers, etc. in the middle of the lake. Great management and a great plan. I dont have a problem with jet skis at all in that situation.
That being said, with all the lakes you have to operate a jet ski on, why is it necessary to allow them in National Parks? For several reasons it makes no sense. One being what I already stated, the parks werent set up for a jet skiers playground. They were set up to allow the public a place to observe nature. I agree that the parks are a far cry from the reality of the outdoors, but they give the public a place to experience the outdoors in a somewhat controlled and organized way. The last thing people go to a place like that for is hear and see a pile of jet skiers. Plus with all the other options available, the fact they close down a couple NP's is almost a moot point.
I just dont think there is a need to allow them in a NP, but I certainly have no problem with them elsewhere.