Sensationalist headline, the emcee is annoying so skip to ~2:25 for the actual quote.
I don't think drug testing for employment should even be legal, but when I worked in HR for a call center at Sprint at *least* 60% of the people who got through all the interviews and only needed to pass a drug test for employment failed the drug test and lost the job.
This is anecdotal but true in my own personal experience. I want to reiterate I don't think it is fair to make a person take a drug test pre-employment but if you know you are going to be tested at least be smart enough to beat the test. I almost got hired at Geico recently, I passed the piss test but they did both a urinalysis as well as a hair test and my hair test popped dirty but my urine was clean. Substituting urine is easy, I don't have any experience with beating hair tests. Luckily urinalysis is much more common than a hair test. Geico is the only company I have ever heard of the does both. Stupid fucking Gecko.
PROTIP: If you are going to apply for a job that drug tests use synthetic urine if you are dirty. In the current economical climate more and more employers are drug testing. Even temporary farm work over the summer in my area requires a GC/MS urinalysis.
EDIT: I'm not sure how relevant this is but for full disclosure Philadelphia has actually decriminalized cannabis usage. This may be part of the reason a large pool of the the applicants piss dirty for marijuana. Where I worked at Sprint as previously mentioned in this post (Ohio) marijuana was also decriminalized. It seems kind of fucked up to me to decriminalize an act only to discriminate against those who are not even breaking a law (Yes, they are breaking federal law but that is a whole different discussion)