But, alcohol is something that has been present in our ancestral environment (e.g. fermented fruits). If anyone's telling me, our bodies didn't learn to at least tolerate small amounts of it without any major side effects, I'm going to be asking a lot of follow-up questions.
I think it's much easier to argue this case than, say, tobacco or "drugs", which are arguably more recent inventions, depending on your exact definition of drug.
It's cancerous.
The problem with highly addictive things is people do not stop at small quantities.