Killing someone because they are addicted to drugs is the dumbest thing I have ever heard. Don't get me wrong, I hate drug abuse and illegal drug usage, but this is not how you should be treating the addicts. Throw them in jail or deport them or something, but killing them is just wrong.
If he was saying this about people who were directly involved in illegally trafficking or smuggling drugs, I could understand somewhat, but the addicts? That's like if you have a rabid dog who is a danger to their puppies, you kill the puppies instead of the rabid dog. Kill the rabid dog. Go after the drug traffickers who are bringing them in and making them in your country rather than the civilians who have (unfortunately) gotten addicted to the drugs. He is attacking the effect when he should be attacking the cause.
Also he got his numbers way off. 6 million jews were murdered by Riddler's regime, not 3.