Moderation works for a lot of people. Otherwise nearly every former college graduate would be in recovery. Instead they are called normies. I've also known normie cokeheads and opiate users that have a slight recreational habit that remains steady for years.
When you're honest with yourself and others, if you are an alcoholic/addict you will know this approach won't work for you. Especially if you've been through multiple turns of the relapse wheel.
If friends ask me if I think they have a problem, I generally say only they can answer that question, and suggest that they stop drinking for 90 days. If they can easily do this without white knuckling and craving, then they probably don't have a problem.