I think part of the reasoning might be what you said in your opening post:
Originally Posted by blackngold
Those teams barely even have any fighters on them!
The rest of the reasoning is, why bother fighting if your team is winning? One of the main reasons fighting exists in hockey for teams is to inject some energy into your own team to get the rest of the players to "fight" for the win. If your team is already winning and the other team isn't willing to put in the fight, it just isn't going to happen. Is that a brand of hockey we like to see? Surely not, but in this shortened season most teams wont be able to "fight" every night.