Andrew, my conclusion based on the facts you enumerated is the Izzo is a jerk. I also have some corroborating evidence from other sources that also point in that direction.
I've had some extensive direct dealings with Izzo before and in my experience, he is a great person. Like you, I had a similar (unfounded) assessment of him before I met him, but he really seems to be one of the nice guys in college basketball.
He may very well have been a jerk about KK, but I can't say the same thing about him overall. Obviously, everyone has different experiences with different people.