It's simple: Lawlessness. When you remove the restraint, lawlessness abounds.
Have you heard the doctrine of the Total Depravity of Man? It states that man will degenerate to the lowest state that God will allow. Since the laws restraining persons from intoxication in this manner have been taken away, the state of Colorado will experience an marked increase in lawlessness and degeneracy.
I see from your post that you believe the opposite will happen and that police will be able to focus on "real crimes". However the real crime of mankind is to willingly violate the Laws of God, intoxicating themselves on what is not profitable and not being filled with the Holy Spirit for which they had be created by God. Rather than dedicate themselves to righteousness: loving thy neighbor as thyself and raising children in the nurture and admonition of the Lord, they will be given over to their own passions and desires.
My prayer is that this sin would accelerate, burn out, folks repent and asked to be delivered from such affliction as this will inevitably produce and that they and their land would be healed. For if it is not checked the affliction may be intergenerational.
So why not ban drinking alcohol since that is a base state of man? FYI the lord does not set the rules for the country. It is the US constitution.