What Webber did was a pre-meditated assault on Stockton. What Karl did was a highly aggressive play on Isaiah. He didn't plan it before the game started. He intended to stop him from going to the basket when Isaiah was making a move. It was an aggressive play by Malone, and it resulted in an injury to Isaiah.

Wasn't the first and won't be the last of aggressive plays by athletes trying to protect their end zone/basket/goal, etc. The key here is that Malone didn't make a decision a priori to go out and hurt Isaiah, while Webber determined prior to the game that he was going to get Stockton to "set a tone".

Malone got thrown out of the game and suspended for another game (or two) for what he did. If I remember correctly, Webber got a personal foul and nothing else.