- "and if they hadn't gotten it from the silk road they'd have gotten it elsewhere"

That's very unlikely to be true in the case of the high-school kid who died buying a synthetic drug off the internet. They almost certainly did not have a dealer connection sophisticated enough to sell that. They almost certainly would have lived, if Silk Road were not available to them at that point in their life.

You're advancing an argument about drug markets and personal autonomy in the general case, but it's a very poor fit to the concrete facts in the specific situation we're looking at.