Not a hockey fan either, but I’ve often asked this question of my friends that are. They all same the same thing: The fans enjoy and expect it. To me, it’s dumb. One team ends up a player (or two) down, and that’s when a lot fo the scoring happens. Ergo, you fight and you are more likely to lose. Pretty much any other sport in the world and you’re off the field of play, and often for a long period of time.

FWIW, this is also why I’m not a hockey fan…

You seem to misunderstand how the penalties work out. 95% of the time after a fight happens, both teams get offsetting penalties, and so neither team is at a disadvantage because of the fight alone. There are instances where one team ends up with more penalties after a fight, but it’s usually because of something that happened before the fight and prompted the fight (and should’ve been a penalty anyway)

They added the instigator penalty to cut down fights as well. The player deemed responsible for startibg the fight gets an extra penalty, and that does indeed give the other team an advantage.