I'm guessing that if the grandparents had been good parents themselves, they wouldn't be in this position of having to raise the children of failed parents.
Parenting is learned from parents (how to/how not to). If the grandparents were poor parents, their parents get some of that blame. Grandparents were just trying to apply some of the lessons they learned firsthand while they were figuring it out. That, and no matter what you teach your kids, they have to embrace it. Ultimately, they choose.
That said, Some areas and demographics were heavily targeted by radicals in the 1960s, and unfortunately, that took hold then and has been spreading since, fostered by government policy which was instrumental in creating the environment of dependency and destruction of the family which went hand in hand during the implementation of the Great Society.
The problem has deep roots that go back to the '60s, and I recall when the path to success was something that would be called "acting white", get an education through athletic scholarship or academic scholarship, or join the military and get one on the GI Bill--and not in grievance studies, but in engineering, medicine, or law, or some other professional track. Many others sought becoming proficient in trades.
That paradigm shifted with a combination of widespread drug use, fomented racial animosity, and the growth of the socialist nanny state.
But LBJ got his votes...