Robert Upshaw was suspended twice in his freshman year at Fresno State, before being banished for good after two suspensions didn't get the message through. At the same time, Robert Upshaw was the highest-rated recruit EVER at Fresno State. They beat out schools like Arizona, UCLA, and Louisville for him. To banish him after a year must tell you how much of a bad influence he was. Having a guy like Upshaw around to dominate a smaller conference like the WAC produces the type of success that earns coaches large extensions or jobs at higher-profile schools. That Fresno State decided, in less than a year, that they were better without him says a ton.
The following year, Upshaw landed at Washington. Due to NCAA transfer rules, he had to sit out the season. Halfway through that season, in which he was only allowed to practice, and not play, the coach told him to stay away from the team. Then this year, despite being a completely dominant center, he was again kicked off the team in the middle of the season.
This isn't a player who would be getting a second chance. He arguably wouldn't be getting a third chance. He's literally been kicked off his team three years in a row. NBA coaches don't have time to deal with that sort of nonsense playing 4 games in four cities over five days. Taking him at #16 overall would be pure folly, and at 28 would probably be regrettable.
Also, he's talented, but let's be clear -- even if he didn't get kicked off his team for the second time, he would be lucky to be picked before #10. You're not talking about getting someone with the talent and athleticism of Karl-Anthony Towns but with character flaws. You're talking about getting someone who's around Myles Turner level, but with character flaws. The value simply isn't there at 16 for the outsized risk that he brings with him.