Drinking is a big part of Korean culture - that's not news. Drinking is heavily encouraged almost everywhere.
Public intoxication is not a crime here (or if it is, it is never enforced). It's not uncommon to see grown men passed out in parks or on the sidewalk. Hiking groups carry soju and beer with them on the hike to drink along the way. Beer is sold on trains and in bus stations for the ride.
Perhaps one of the most transparent endorsements of public drinking is the attitudes of convenience store owners. They keep corkscrews and bottle openers behind the counter, so you don't have to wait until you get home to enjoy your adult beverage. You can drink it on your way out the door.