i can't really say that they are targeting one in particular group unless you just want to consider being the drivers of cars a "group". I have had a deputy with the local constable's office tell me that they use traffic stops as a means to try and solve other crimes that take place in the area. If they can pull someone over then they can start questioning the driver and or passengers about other things which might lead to some leads or arrests.
When things are in place to give an incentive to them for confiscating items and cash they start getting real aggressive in how they go about doing it.