judgements from the usual court system are enforced by the police, who are authorized to use force - i.e. violence - in the event of non-compliance. this is not a unique feature of the drug trade.
well, perhaps if there was no state, there could be another mechanism which is comparable or better, but when contract enforcement in a particular area is excluded from state enforcement, while normal areas aren’t, I expect the violence used in that area to be worse.