The bars aren't really the problem. The drunkards are. I think that's the optic a lot of people resent. If someone wants to grab a beer or a cocktail - enjoy their beverage - then go about their day. More power to them.
But that's usually not how things happen. See: Drinking Teams - When people come into a theme park with the express objective of getting hammered and wear attire that markets it to everyone, then yeah, it becomes a problem. When they make assclowns out of themselves - and become loud, obnoxious, and sometimes aggressive - it impacts everybody.
Not saying that is what it will evolve to at MK. But that's what it has evolved to at EPCOT.
Personally, I could care less if Disney sells alcohol or not in the MK. I do care (and very much care) if they don't have a plan control those who get out of hand.