Legal consistency has many benefits. The two that first come to mind are:

• making it easier for non-experts to reason about the law

• consistency is, in my experience, usually a property of fairness

Let's keep it practical. Alcohol is here to stay and will not be prohibited. For historical reasons, culture, whatever...it stays.

Yet other harmful substances are currently banned and you opt to unban them for...consistency. It's like saying when two countries are at war, why can't we all be at war? Seems "unfair".