Di Canio says he had no option but to punish the right-back.
"We have a fantastic, young academy, they have a changing room next to the adults, but if we don't punish this kind of behaviour, we might not be able to talk about a fantastic academy," he said.
"They're not going to sprint down, get the boots and say 'good morning' to everybody. If we don't punish this kind of behaviour, how do they grow up?
"Maybe they will laugh at the picture. Maybe they think it's fantastic; to be like a gangster. But what mentality are we going to deliver?"