If the fans are overly verbally abusive and the home team folks do nothing, take it up with the commissioner.
But physical violence cannot be condoned or excused. Convict this thug of a felony, ruin him financially, and send him back whence he came.
If MLB wants to yank this couple's season tickets, that's fine, too.
The player will likely be ruined,and deservers it for losing control, but I have absolutely no sympathy for these fans. None. They're bullies and drunken thugs, and bullies usually end up with bloody noses when they run across somebody who won't put up with their crap.