I'm not sure it makes much difference. Social drinkers seem to increase the opportunities they have to be at events where they can engage in"social drinking" and some drink to excess. That is why they go to where the drinking is. Some of the most obnoxious people I have run into were "social" drinkers.

Conversely, most alcoholics learn to hide their addiction and most successfully keep it a secret for as long as possible. "Social drinking" usually means everyone is doing it so it doesn't matter.

In both cases, both are addictive behaviors.