Because the carriers are not mosquitoes? "If X is a disease, why is it 'wrong' to attack it or it's vectors in the same way as a biological disease?" Surely you can see what a nonsensical statement that is for many values of X be it substance abuse, gambling, etc.

I don’t. If we’re not going to outlaw substances that have extremely limited therapeutical uses in their current form while allowing corporations to profit by causing great harm to millions of people, you explore other avenues to fix the problem.

I’d offer a vaccine for addiction if one existed, but until that time, you hack around the lack of political will.