Just to play devil's advocate, here, there are a few arguments for it not being a "drug".
Most notably, it is "food". The chemical that causes the effects are also metabolized for energy by your body. Pure alcohol has a calorie content. In excess (for suitably small values of "excess"), it causes problems with neural functions, yes, but so do most other chemicals. Glucose (your body's major source of energy) is carcinogenic in quantity (for suitably large values of "quantity"). Proteins (of which there are many), can be the most deadly poisons to humans.
Alcohol is unique (or at least in a very, very small group) in that it functions as food, poison, and drug, depending on your body's response, its concentration, and several other factors.
I think the only way to unilaterally declare alcohol a drug would be to define drug at a chemical level.
That said, I would not disagree with those who called it a "drug."