The issue with Kronwall — and this was argued about extensively on this board at the time, as I’m sure you both remember — is that he found loopholes to continue with the jumping hits even when (almost) everyone else was already on the same page that this was not “fair game”.
His prime came right when the NHL finally had enough and established anti-headshot rules that amounted to “keep your feet on the ice, elbows tucked, don’t hit blind side”. That was enough to eliminate 99% of the bad actors.
Then there was Kronwall. He figured out that he wouldn’t get suspended for leaving his feet if he jumped at the last second with one toe still on the ice… he wouldn’t get suspended for an elbow if he turned at the last second so that their face went into his backplate… he wouldn’t get suspended for a blindside hit if he could catch them from the front with their head turned the other way.
So even though he was perfectly capable of being an effective hitter while staying away from the headshots, he actively chose to keep on laying guys out with concussions while staying firmly inside those loopholes.
It was just a trash way to play the game, and really not forgivable at a time when the CTE data was already on the table and we had guys like Crosby and Savard barely hanging on to their careers due to head injuries. It’s not like he couldn’t have played another way, he actually made the choice to use that technique to catch unsuspecting targets in the most violent way possible.