In some cases "working for the man" isn't bad and it does give people purpose, but in (imo)the majority of cases, it is bad because it prevents you from using your time to do something you actually find meaningful.
I think the few people who are able to find meaning in their jobs are either extremely lucky to have found what they want to do, had the opportunity to pursue it and succeed, and make a decent enough living doing it without the money aspect killing their joy - or they're the type of people who have just 'over-assimilated' to modern life and found a way to extract meaning from their work, but these people would probably be able to find at least as much meaning and happiness in something else if they grew up in a world where working wasn't expected to be almost your entire life.