Because I think the actual percentage of the population that are alcoholics is relatively (relative being the key term here) small. I used to very regularly joke about people acting like "crack heads" or being alcoholics before I was intimately familiar with what addiction does to people and their families.
Even though my RAH can't drink with me and even though I've lived with his alcoholism it doesn't deter me from wanting to enjoy wine or beer and I used to to scotch tastings with RAH before we had kids.
For normies, drinking alcohol isn't a solitary activity - its a group event and something that you enjoy with a community of people in small amounts and in a responsible manner. It is everywhere but if done responsibly I don't see anything wrong with alcohol as a substance, what I take fault with is the disease of alcoholism and the initial act of drinking as an escape or to solve problems.