I'm surprised this was mentioned at all. There's even newer research that basically shows any amount of alcohol regularly is bad for you.
Of course I'm not implying that alcohol is in any way healthy, but it's probably healthier to have great drunk moments with your friends once in a while than it is to be lonely and not drink. It's important to note that you certainly can be social without alcohol though.
From the conclusion: "Our results show that the safest level of drinking is none."