Murdering the drug abusing population would be frowned upon by anyone with a sense of morality.

You're absolutely correct though that it would be a "final solution" in the "War on Drugs" but implementing it would face a horrendous backlash; although there are quite a few of the population who would support it.

I would consider anyone who is ok with murdering citizens who take drugs as completely out of connection with the reality of drug use/abuse.