Ever considered the possibility that alcohol makes some people feel like they're not themselves, and that's a good thing to them?
Not saying that's an objectively good thing, but it points out a reason. Consider people stricken with social anxiety who have found that medicating with alcohol temporarily cures the problem. Maybe they begin to rely on it and it begins spiraling out of control.
Or maybe another person uses it to forget about all the crap he or she deals with because it takes them to a place where they don't care as much. The state of being becomes an escape, and then their addictive personality grasps onto it until it just goes further into a daily lifestyle that started out as solving a problem, but ended up as being a lifeline.
That starts the addiction... the effect it has on you that ends up positively affecting your state of mind. The reward centers start making a nice, cozy home. The problem arises in the subsequent reliance, and then changes into the reliance of just feeling "normal" because you've been drunk every day for the last 5 years and stopping gets you physically and emotionally sick. You don't want to endure the struggle of a transition back because you know what your sober self was like that put you where you are in the first place, and the transition back is more horrific than the starting point. And all this time, you tell yourself that life is better with the sauce because you're so numb to your own feelings when swimming in it that it just seems like a better existence.
Such a thing can't be judged accurately from an outside perspective. And folks who enjoy a few beers now and then are not in the same category.
In my experience, there are two types of people that enjoy alcohol.
Those who partake every once in a while just to have fun and then leave it at that.
Those who started that way and found it therapeutic for some inner problem, and created a new one that's ultimately far worse.
Source: Am an alcoholic. I belong to category 2. And from the inside looking out, I can tell you that all the words that I have typed in this post are at least true for me, and I'm willing to bet, for others as well. There might even be more reasons. But they're all reasons, and it has absolutely nothing to do with the taste or the first few experiences with alcohol.
It's all about state of mind.