When you wake up from your delusion, you will realize the police are just the opposite. Most are honest, hard working, very tolerant people who have a very difficult job to do. It is hard to be Mr. Friendly to everyone when 90% of the people you deal with are clueless assholes who treat you like shit and think they are Perry Mason and some of those lovely people would rather kill you then go to jail. Most people the police contact are contacted because they have done something wrong (illegal). When was the last time a cop just walked up and said hi for no reason? Likewise, how many people say hi to the police unless they need something?
In this case a bunch of intoxicated, mostly twenty somethings (who think they know everything) engaging in what they think is harmless fun, but unfortunately someone had a problem with it and guys are not supposed to be in the ladies room, no matter how funny the bet may seem. True a small minority of cops of meatheads who love an excuse to smack people around but most of those guys and gals are weeded out sooner or later. Unfortunately some are not. I wasn't there so maybe the cop was wrong, or we are only hearing the side of the story from those upset because their friends or selves got in trouble.
As for tasing, most departments policies justify it when a person engages in physically non-compliant, assaultive, or threatening behavior (assumes a fighting stance, challenges the cop to a fight, resists arrest, etc.). The person tased, does not have to have a weapon.