As much as they try to defend their use of pot they conveniently forget that it is a drug and drugs affect people differently. What the DUmmies are doing is broadbrushing positively.
I grew up knowing no one who hadn't tried smoking. There were some incidents of violence after use and at least one suicide attempt. For the most part people didn't tend to do much after smoking, but when they did do something it was entirely idiotic. When they were faced with no money for their munchies or for more pot they could bestir themselves long enough to thieve.
The DUmmies omit that what pot does do to almost everyone who smokes it regularly is to eliminate initiative. And, it doesn't entirely change the personality even then. If someone has thuggish, dangerous, aggressive tendencies the pot isn't going to make them an instant tree hugger.