You can not draw a direct parallel to drinking, we have the technology to quantify how drunk someone is. So if they perform an action we can evaluate how much the alcohol effected the outcome.
I am not sure, if it should be legal or not.
But legalizing it would generate some serious problems.
For example;
Intoxicated driving, if someone is not allowed to drive high, when do they start being high and when are they nolonger high?
The other problem is that pot is not always the same, so if you expect a certain result from joint A but its made with pot B, how do you control that?
It would be like having beer that had no labels and one bottle had 3.5% alcohol and the next bottle was 30%. This make responsible use dificult.
I do understand the case for pot use;
I do agree that sending someone to jail for pot use or selling is just dumb. And that those funds could be used much better for building a park or a ballpark.
Canada has a funny law, smoking in a public hall (Octoberfest) is a $189 finr and smoking pot in the same place is a $79 fine. (I have never received either fine, I do not smoke).
I guess the bottom line is do whatever you want in your house, but I do not want to get killed because some pothead decides he need chips and gets in a car while they are high.