If this is the standard for being arrested, you could have arrested someone at almost every party I went to when I was at Michigan.
One of the witnesses said he often visited the house as was allowed to come and go as he pleased. Yeah, he should have left when they told him to, but it wasn't like he was breaking into some random house. It was clearly a place he visited often and he knew the people involved. If he had actually been pummelling someone I could understand the arrest, but it sounds like he was just worked up about something one of the guys had done.
This seems really weak to even arrest him, let alone charge him. If the women who stopped him are testifying that they weren't even concerned about him hurting them he must not have been totally out of control. Sounds like a 3rd party came upon the situation and overreacted by calling the police.