Opium and alcohol were powerful intoxicants - and legal - in 1790.
And here he is again telling half-truths. Opium was very uncommon in the United States in 1790. There was no market for it and little supply. Most of the people who had access to it were Doctors. It was used as a medicine, not as a recreational pastime.
Alcohol has been with humanity for 10 million years, and it is caused by fermentation. It is ubiquitous in availability, and in human history.