That explains it: The director was white

There was never any doubt that the perpetrators, beneficiaries of the project, were primarily to blame for the vandalism. What the movie asks is, how did this situation come to fruition? What conditions produced a population willing to foul their own living space and how was it possible for the vandals to get away with it?

I submit that the motives behind the project were flawed from the beginning. White liberal do-gooders, believing in their own goodness, created a massive do-gooder project to elevate their inferiors from the mire of poverty and ignorance and bring them into the middle class without ever examining the possible consequences. As in all urban ghettos, conditions are created by government largesse which allow the worst, the most violent, most dysfunctional and least able to live with others to be concentrated in a single geographical area. That these criminal types exist in every society is a given, but to bring them all together in one relative small space where they can do the most amount of damage takes a massive amount of government money.

The filmmakers here buy into the liberal myth: they point to changes in demographics in St. Louis at the time like the rise in unemployment and general flight to the suburbs as causes of the collapse of Pruitt-Igoe. They consistently refuse to see that there is something fundamentally wrong with the whole concept of do-gooderism by big government. They never examine the possibility that you can't solve social problems by throwing money at them. The filmmakers are part of the vast liberal conspiracy to uplift the lower classes and can't see that they're the problem, not the solution. They couldn't see that giving welfare to teenage mothers was encouraging teenagers to get pregnant to be able to collect welfare. At the same time the young men were rendered useless and you got this epidemic of unwed births.