Let me chime in as someone who has played basketball in the not-so-distant past...
Grayson Allen is absolutely a punk. I get this vibe from everything he does. I used to play a lot with a kid just like him, and I had to put him on his ass more than once. He's a far cry from a school shooting (I hope?) but what he's doing isn't "nothing" either. Terribly poor sport. I hope he tries to make it in the NBA. He's not going to respond well to being the little guy.
As for the "shove," absolutely a shove. The victim coach took the high road. That is a completely unnatural move to make in that situation. Guys go for loose balls all the time at all levels, myself included, and I've never seen someone do that in an effort to mitigate the damage. What it IS, is something a punk would do.
He's not worth the press he's getting, but he's definitely a little piece of shit. I'm guessing he grew up in a very protected environment. If he tried any of that stuff in an area that his parents didn't donate to he'd probably be in a wheelchair by now.