In NY, grocery stores and convenience stores don't allow you to sell alcohol over a certain percentage, does anyone know why or how that came to be?
In NYC you need to have a certain type of license to sell beer and/or wine in a grocery or convenience store. Grocery stores don't sell liquor. I know that has to do with some laws around when alcohol was made legal again after prohibition. I live in NYC and it's also a sentiment that not selling liquor in grocery stores and most grocery stores not selling wine is what helps keep independent wine and liquor stores in business.
Laws and ordinances often depend on who had the best lobbyists. A good example: In Montana, liquor stores have to close on Sundays. Bars, however, can get a bottle license allowing them to sell full unopened bottles of liquor, and most bars are open on Sundays. This means that you can still buy your bottle of whisky on Sunday, but you have to go to a bar (and probably pay more) instead of a liquor store.
How did such a thing come about? The Montana Tavern Association has a very strong lobbying presence, but liquor store owners don't.
I'm sure everyone has similar examples from their area.
TL,DR: Most liquor-related laws in the U.S. make little sense.