I think
this reply sums it up.
Mark Jackson also reportedly tried to unite the locker room by having them
turn on Festus Ezeli after lying about Ezeli being happy they were losing while he was injured (supposedly to unite the rest of the roster), and made it clear that he wouldn't welcome a gay player on his team. Now, Ezeli has disputed those claims, so that may not be true or there may be more to the story, but his other remarks
are indeed something he's said.
There are also stories about him not wanting to hire top assistants for fear they might take his job, fostering a divide between the players and the front office, and going back to his playing days, trying to turn the locker room against an ageing John Stockton in his final year when Jackson was his backup in Utah (and past his prime himself, mind you). I'd suggest that at the very least, teams may be concerned that he'll cultivate a toxic atmosphere, or be a potential PR nightmare, and are steering clear of him. If so, he has to take some responsibility for earning that reputation.