the most obvious example of harm is probably the opiod epidemic, and the deaths resulting from overdose. of course shutting down the silk road and sending addicts into the streets or to jail is probably exacerbating the risks and is certainly no solution.
I think if anything, the opioid epidemic was improved through dark web market places. I'm sure if you search on the news throughout the years, there were more overdoses related to substances sold being misrepresented or cut with something like fentanyl.
