You straight assuming that people are solely looking at this year's version of Kuzma is --- well, silly. It's called confirmation bias.
Some people just don't believe he's that great a player. Or, at the very least, not good enough to trade Bogi or Belly for or to deal with a division and hated rival.
@Joshoua is spot on about his defense. It's 'turrible' to quote Charles Barkley. The KINGS have enough players that can score but not defend. They've got that market cornered.
Bogi is a better all-around player by far and Belly is every bit as good a deep shooter as Kuz. So what's the point?
It seems to me that some fans are just in on making changes for the sake of making changes. But that's not necessarily gonna make the team any better.
Meanwhile, it remains a pretty smart tactic not to help improve a team you hope to be competing against for division and playoffs in the near future and that just happens to be a hated rival. Believe it or not, they won't have LBJ for all that much longer. Dude will be 36 yo later this year.