I think some people get a little fanatical about what constitutes alcoholism. I'll go through periods where I'll have 3-4 drinks a night for a couple weeks, and sometimes I won't have any for a long strech. For me, it's no different than how I'll sometimes crave pizza for a couple days in a row, but sometimes I don't feel like it for a long stretch.
I think some of the difference has to do with what you get out of drinking. I drink because it tastes good, but some people will drink anything they can get their hands on just to get drunk. Sometimes I'm in the mood for a drink, but I've run out of the particular scotch I was in the mood for, and I end up not drinking anything (despite having an otherwise fully stocked bar). I have no interest in medication to make me drink less...when I want to drink less, I just drink less. Sometimes I stop drinking for a while to lose weight, but I definitely miss the pizza more than the drink when I do that.