None of those tests measure killer instinct which is what the other team measured. If I remember correctly, the decision had something in large part to do with Exum's eyes. Sounded funny then, but has turned out to be an accurate assessment.
The stuff the Jazz measured sound more like they were testing his basketball IQ, which is a different thing, and those things can be learned. The killer instinct, I believe, is learned at a young age, and like learning to pronounce the letter r, once past a certain age you can no longer learn it.
Also, I would put money that the "washed-up former point guard" would play better than our starting point guard if he were on our team. He even produced better stats and for the most part played better than George Hill in last nights game, so it's pretty ridiculous that you're claiming he's washed up.