So, these Euro clubs view the players as assets. Not only was Yurtseven desirable because he was an NBA caliber big with good skills who could help their team win, but also because when he eventually goes to the NBA, the club would have to be reimbursed millions of dollars for Yurtseven to be bought out of his contract.
So despite Yurtseven saying that he wanted to play collegiate ball, it was in the interest of the club to pay him to remove that option and secure him as a long-term asset. The kid [apparently] wasn't necessarily on board with signing and didn't spend the money, which pissed the club off. And they were doubly pissed because they invested time in the kid, only to lose him without any compensation.
Again, I'm not defending Yurtseven, but that's the way the relevant facts appeared when we were recruiting him over the summer. That he got paid by a professional club that he was affiliated with would be a disqualifier--and justifiably so--under most circumstances. That he didn't want to be paid and ostensibly didn't spend it is what gives him the out.