Smith was laughing when the joke first happened and then all of a sudden walks on stage. There was no passion for protecting his wife. What happened was he looked to his left, saw her face and said "oh shit, if I dont do something she is going to be emotionally 'entangled' with another guy again" and completely overreacted.
Everyone knows you go to these shows and its a mini roast. The "its funny untils its me" mentality dont fly.
Smith should have been escorted out immediately. As for charges, I dont know if I woulda filed any because they probably know each other and Rock is wondering wth is going on in Wills life for him to react like that on national TV.
And I guarantee, Smith wouldnt have tried that if it has been The Rock on stage instead of Chris Rock.