This is a cultural aspect deeply rooted in social and cultural norms. Koreans, who are generally shy and not as open as those in Western cultures, perceive the behavior associated with alcohol as positive. It facilitates bonding and the sharing of their lives, feelings, and stories. When they drink, they can express their opinions more openly.
So, while some people may view alcohol negatively (for instance, I only drink occasionally), others, particularly in this cultural context, may find it necessary for social interaction.