It seems that the end result of this would be an increase in crime, as many drug addicts would likely turn to crime instead of gainful employment.
It seems that you are saying that legalized theft by congress (forced taxation to feed drug users or non-citizens) is preferable to illegal theft by the drug users/non citizens (which brings probation, jail time or deportation) to feed themselves.
Why? We have no recourse when congress decides to confiscate and distribute our earnings, but we do have legal recourse when individuals do. I also find it hard to believe that food stamps are the one thing standing between drug users and the additional crime of theft.