Not a documentary, but Sex and the City was the most culturally damaging piece of media to millennial/gen x women. It convinced so many that being single, banging every mildly fuckable guy, living in a bug hive, getting shit faced drunk, acting loud/obnoxious/blunt/vulgar, having a high powered career, and consoomerism was the best way to live. People are starting to come around and realize that was an utter lie, but there was a good 25 year run there of women dropping soul fulfillment for bottomless hedonism in mass. I think someone could write a thesis about it being the most successful piece of propaganda of all time and how.
Supersize me also brought on the streamlined boring ass McDonalds of today because its message was that advertising unhealthy food to children was wrong. So they took away all the colors and playplaces.