It's always best (IMO) to assume the best when you don't have all the information necessary to draw conclusions. I agree with those who see this as a young man whose emotions simply let loose for a period of time, perhaps frustrated with himself and perhaps simultaneously frustrated/embarrassed at being called out by a teammate.
He was frustrated, he swore, yelled, looked angry, shed a few tears. He didn't swing fists, get physical with his teammates, throw chairs, storm off the court. A few minutes later, he made what appeared a conciliatory gesture in his high five to KG. I don't think there is anything either to worry about or make fun of -- at least based on what information is available to date.
And on another but related note -- BBD tears may flow a bit easily, but there is another Celtic who has been known to cry from time to time. They call him the Big Ticket.