I tend to think that anyone who could afford to drink alcohol before there was clean drinking water did so as a matter of good practice. When that happens there is alway a propensity to become an alcoholic. It’s not that big of a deal when everyone else is going around half drunk too.
In Alexander’s case it was more a problem with how he behaved when he was in the cups. It was a problem that bothered him. His men had to restrain him from killing himself after he ran Clitus through during a drinking bout. He sacked and burned Persepolis to the ground... another ‘idea’ he got while at a drinking party that he probably regretted afterwards. When his friend Hephaestion (the only person he probably actually loved) died he went into a long inordinate mourning. Alexander was not a Stoic... It was those personality traits that came to the fore when he was drinking that were a problem.
...And it made ugly girls look hot on a Saturday night...
Good point! Even children drank beer and wine because of water impurities.