I mean, every knee injury is technically weight related. The point is, we dont know what caused this injury. We dont know if he would have sustained the same energy if he was 15lbs lighter, 30 lbs lighter, etc. There are too many factors to consider before you come to the conclusion a player NEEDS to lose weight.
What we do know is that because of his gait, landing mechanics, BA, his body still
growing and simultaneously trying to map out a course of its own functionality, and his reckless, physical, and high-paint activity style of play, that in itself, is a cocktail of doom. But when we add in the fact that he's playing at an incomparable weight, that players who're 4, 5, 6+ inches taller aren't even tipping the scales at, we've entered territory where it's become the
inevitable (as I've said time and time again).
The problem with you is, for whatever reason, you got it in your head a long time ago that he doesn't need to lose weight, and are now trying to fit the pieces around that to where you're keeping up that fictive, even it goes against all common sense, the nature of the game, opinions of physicians, and most importantly, reality.
More weight = more stress on body.
That's about as layman as we can get. And yet here we are with you playing dumb to ignore the culmination of stress he's put his body under. Especially where he exists in a game that has more running/covering of distance, more jumping and moving at angles, than it ever has before, that even the standard-NBA body type isn't made for.
Suppose we can prove zion chances of getting injured would decrease by 2% if he loses 20lbs. Does that risk outweigh the benefit of having that mass? His mass and strength is probably his biggest advantage right now. That's the type of stuff you consider before ordering a player to lose weight. As Griffin pointed out, it could be a matter of strengthening his core opposed to shedding weight.
Are you really asking if the benefit of decreasing the risk of injury, where he'd increase his chances of having an
actual career, outweighs the benefit of him playing a certain way, all at the cost of him lowering the chances of having an actual career?
You can change the way you play; you can't change shyt if your career is over.
This is partly the reason why I said the success he has at the NBA-level is down to him developing an outside game, because he's not going to be able to truly dominate with his style of play, especially in his current state of weight.
There are far, far, far too many factors standing in his way: his body won't let him, the war of attrition that is the season won't let him, his SOP won't let him, length / size / experience at the NBA-level won't let him, coaching, game-planning, and adjustments won't let him.
Losing weight and changing/adapting his style of play is the only way.