At the same time...
ODs frequently happen because of lack quality control. You get this stuff from some shady folks, who got it from other shady folks, you have no idea whether you can trust the dosage, or whether you even get the drug you paid for.
The drugs themselves are often not the problem.
You can kill yourself with alcohol and nicotine is one of _the_ most additive substances we know. Should be prohibit these as well?
The key is regulation and quality control, and that you can only do within a legal framework.