I think this problem could be interpreted as in an “externalities” context. Since the “at attack to humanity” could be interpreted as a cost to drugs consumers for having drugs available, the cost is actually not diluted among the drugs consumers, they have to pay prices that are much higher than the marginal cost of producing drugs. So in the drug’s market price this cost is reflected as a “market premium” everytime we consider drugs would be cheaper if they were legal (which is not an unrealistic assumption and has happened in many places were certain drugs became legal). But the real problem is that the “attack to humanity” generates an externality for non-drugs consumers, which is a common externality in places where drugs are illegal. This does not mean that legalization is a costless solution. The drugs legalization carries out another problem in the context of externalities: the cost for society to have drugs available in the market.
A reasonable public policy on drugs should take into account both costs to society and legalize them only if the benefit of doing so (or the reduction in costs) is at least as much as the cost of having drugs available to the market, which are often not easy to calculate.