In contrast, despite a factually inaccurate belief on the part of right wing nuts about drug use, it does not turn out to be a prevalent problem among those in need of public assistance.
So of course, instead of drug testing gun buyers, the right tests poor people who can't afford to use recreational drugs, and to deny medical assistance to those who have previously used drugs and need help dealing with drug use as a medical issue. Instead the right spends a lot of money on incarceration that could be better spent elsewhere.
We have obstruction from the right, not because the idea of drug testing people prior to gun use is a bad idea, or not drug testing people for public assistance has proven to be a good idea, but because it doesn't FEEL good to Republicans and other righties.