Why are the Nigerians being targetted? There has to be a demand so there is supply. The first rule of economics is that if there is no demand for a product, there is no market for the product. Simple.
Further, this is not a case of "forced conversion" where people are being forced to partake in Cocaine consumption. Deal with the demand and supply will dwindle and eventually cease. Also, it’s not as if Nigerians manufacture the drugs here. They are mere couriers. Go after the guys that employ the Nigerians.
The media's role in this is also suspect. The Rahul Mahajan's case has been over-dramatised that it could become a soap opera or even a mini series. Pages of newspapers are just devoted to this issue. Is there no newsworthy item anymore in India that the tragedy of a family should be thrust down our throats everyday?