Fairness of severness of celebration penalization

Yes, the title does rhyme. And I just wanted to bring this to attention, if a safety goes helmet to helmet on a defenseless wide receiver, knocking him out and sidelining him with a concussion, how many yards is his team penalized? 15 yards. If a player slam dunks a football on the uprights how many yards is he penalized? 15 yards. Notice a problem? With all penalization, the punishment should match the crime. If bruising a players brain results in 15 yards, should a break dance after a TD result in the same thing? If they are going to have such a rule in the game then they need to get rid of the flaws that are present. It needs to have a more clear cut definition and a much more just punishment.