It may have seemed funny and brutal, but was completely inappropriate on the part of all of the guys involved. Exploited the situation for humor and ratings. If he was a half-way decent human being he would know that crap like that is private. You don't do shit like that. And if she was smart she would have said "I am not going to discuss anything about our relationship in public" - CLICK.
If it were a normal break up, then yes - making it public would be kind of inappropriate and douchey. But since she cheated she deserved the public pwnage and hopefully all her friends heard the entire thing.