Like the other person said, it was for selling, not taking. Also, I think someone should have the power to keep the public safe, whether government, or a society-sponsored group.

The cops were undercover DEA with previous experience going underground in places like Colombia. They had been in rough places. Their focus was mainly hunting the big guys: suppliers. End-chain young people trying to make a quick buck is low yield, and if anything going after them distracts from the root of the problem and alerts the big guys.