The argument for online drug marketplaces, as I understand it, is that it reduces violence since there is no longer a physical 'turf war' component. So, if people were going to buy drugs anyway, this offers a safe, nonviolent space in which to do it. It avoids an environment where dealers are shooting each other and innocent bystanders.
With regards to violence, just because Russ was silly enough to think that you could hire a real hitman over the internet doesn't mean that it's a real thing that happens.
Again, I'm not disagreeing with you. I just want to fling some spaghetti and see what sticks.