Your logic makes no sense.
If no one wants drugs there are no drug dealers.
Here is an experiment for you. Go get a bunch of rotary phones and try to sell them on a street corner. Come back and tell me how many you sold to people that use them as their primary phone.
Drug dealers sell drugs because there is a demand for them. Drug dealers by selling drugs cause a lot of pain in peoples lives and you certainly can argue the morality of selling drugs.