As an analogy. As far as I know heart disease is one of the main causes of healthcare costs and death. Obesity leads to an increased risk of heart disease. Does this mean that we should have a government mandated diet to eliminate obesity?
In that context, you're getting slapped because you're ignoring the fetid mess that the US drug policy has caused, and that our current drug policy is not being very effective for public health or public spending:
(a) It's horribly racially biased:
(b) It's incredible expensive (ibid), to the tune of billions of dollars per year in paying for enforcement, incarceration, and lost productivity;
(c) It doesn't obviously reduce use rates!
You don't have to be a fan of drug use to appreciate this mess. I'm not - speaking personally, I'm about as negative about the issue as one can get, for drugs, alcohol, and tobacco all together. But that's not the point. Barring some actually worthwhile, cost-effective, and fair method of enforcement, which nobody in the US has stumbled upon yet, we need to stop pissing away money putting nearly 1% of our population in jail  where not only do we burden them forever with a criminal conviction, we introduce them to a lot of real criminals and set them on the path to real crime.
Putting someone in jail in NYC for a year costs $167,000 . Surely we could do some more effective prevention and education with that money. Or take it and try to reduce alcohol DUI fatalities or tobacco use, both of which are currently more deadly than pot use.