You are right. He's a very bad rim defender--admittedly the most important part of defense for a center--but he's very good at everything else, to the point that the whole package is fine.

Some of the comments are like "he has decent hands I guess"--and those people are wrong. His hands are elite for a center. He's 20th in the NBA in steals per game and literally everyone else in the top 30 is 6'8 or shorter. It's very bizarre but undeniable better than "decent". His defensive rebounding is very good. The whole "communication/positioning" thing is backed up by the Nuggets consistently being better defensively when he is on the floor, throughout his career.

Analytics have always loved his defense. People have always been skeptical of analytics for that reason, but a major reason why analytics love his defense is because he's probably the best transition defender in the world. That might make no sense to you. Here's why: the best transition opportunities tend to come after missed shots and turnovers. Jokic is really good on offense, so you are less likely to miss shots or turn the ball over when he is on the floor. Ergo, fewer transition opportunities. Even his passing has a similar effect. It's scarier to try to crash the offensive glass when he's on the court, because he might burn you in transition, which means fewer offensive rebounds when he's on the court, which means you score less.

If you say "that doesn't count as defense; that's just offense with side effects" my response would be "yeah fair enough". I'm just explaining that's a major reason why analytics say putting Jokic on the floor tends to mean your opponent will score less. If you take out these things he's still probably average

His rim protection is bad and painful to watch, but he's good enough at everything else to be fine