I think that the applicable paralel is the rule that requires bench players to stay on the bench when a brawl erupts on the court. You can see over & over that players are tempted to run onto the court when something happens, but most of the time they stop. This is because of Stern's automatic suspension rule that became NBA "law" in 1994/95.
I think that something else is worth mentioning. Getting hit in the face with a beer does not give you carte blanche to punch somebody out. For those who think that Mr.Stern was unjustified or overzealous, we'll see when the players who attacked fans are put on trial & threatened with jail time. Mr. Stern's punishment will not look so bad compared to being charged with a crime.
Here's another one. Since when does it prove that you're a man because you choose to fight ? This proves that you are still a CHILD emotinally.

charlie sifford and jackie robinson suffered far more abuse than these nba players and had the courage and dignity to act like a man