Again, you’re penalizing Kuzma for the Lakers’ horrible roster construction and the incompetence of the front office in destroying team morale, while giving a pass to other players on horrible teams.
Kuzma’s individual Net On Rating (–1.2) was better than Collins (-1.9), Bryant (-3.6), Allen (-2.7), Markkanen (-5.7).
As you point out correctly, we can’t look at stats without knowing the context. Magic and Pelinka were a non-stop clown show in the NBA, while the coaching staff has done a terrible job of developing young players and putting in a place an efficient offensive system. The Nets and Hawks coaches have given their young teams some structure. God, even Scott Brooks has done a better job dealing with the Wizards’ implosion (thanks to the injuries of Wall and Howard) than Luke Walton.
Finally, there’s no way I put three centers on the second team. Bryant (6–11, 250) is a center, as are Adebayo (6–10, 255) and Allen (6–11, 237). Even Collins (6–10, 235) and Markkanen (7–0, 240) can play center.
Kuzma (6–9, 220) is a small forward being forced to play out of position because LeBron never wanted to have to guard power forwards.
Of course his defense and rebounding are going to suffer if he is plays against taller guys who are 20–30 pounds heavier.