I remember growing up in the 80's as the youngest of three boys being raised by mom who was much in thrall to Ronald Reagan. To this day, she is given to making claims like, "A lot of homeless people live like that because they want to."
Another claim I frequently heard was that you couldn't help homeless people because if you gave them any money they would just spend it on booze. To her credit, though, my mom never ventured into the realm of dismissive arguments about racial inequality--mostly, I assume, because I was too ignorant as a kid to know it was a problem I should ask about.
Just today I signed onto my facebook page and saw that one of my friends had joined a group called Making Drug Tests Required to Get Welfare. I'm sure that a large percentage of people receiving welfare are in fact addicted to one drug or another, and so making them take a test would certainly mean less of our public treasure getting doled out to these supposedly "undeserving" people. But this very notion of deserving assumes a type of supernatural rising above material circumstances that simply, well, doesn't occur in nature. We have rather another manifestation of the tragically naive notion of free will that lies at the heart of conservative thinking.
According to this dualist view (spirit controls body), people choose to experiment with drugs or not, and the outcome of those experiments is purely a matter of personal responsibility. Moreover, if you're going to choose to get hooked on drugs, then you've forfeited any right you had to a helping hand.
If this view really were true, it would be a great comfort to those of us who are already comfortably well off. Because it's undeniable that poor people have a lot more problems with addiction than middle or upper class people do, if addiction were purely a matter of personal choice, then we could dismiss their plight as resulting from their own bad decisions. Indeed, this is the standard conservative thinking.
A 2002 study published in the journal Nature Neuroscience provides a much more realistic model for conceptualizing the relationship between social status and addiction. The researchers gave individually housed macaques access to cocaine and did PET scans of their brains to monitor the effects. They then released the monkeys into a common space, which prompted them to begin competing for status. What they found once a hierarchy had been established was that dominant monkeys showed an increase in the amount of dopamine receptors in their brains, while subordinate monkeys showed no change.
How this difference in dopamine receptors manifested itself in the animals' behavior is that the dominant monkeys ceased administering cocaine to themselves, while the subordinate ones were more likely to become addicted.
Insisting that welfare recipients take drug tests is simply further disadvantaging the already disadvantaged. A better idea is to favor policies that reduce income and wealth inequalities. Providing equal access to quality education and health care wouldn't hurt either.