Lets say you bought a phone from Craigslist and its a fake one, what do you do?
You sent a guy a wire for a collectors item and he sends you a box of rocks? What do you do?
There's so many ways that you can get scammed in the real world without recourse.
What's happening here is that you have a preconceived notion of "darknets markets bad"
I have bought and sold on Craigslist. This is not how it works --- unless you're stupid.
What's happening here is that you have a preconceived notion of "darknets markets bad"
Yes. People choose to operate on the darknet instead of craigslist for a reason --- usually because they are doing something illegal. And scamming people is one of these illegal things.
Escrows, vendor reputation, feedback, etc?
Something illegal depending on the jurisdiction
Legal =/= ethical