I, too, read the Oprah essay, but came away with a gentler view of the mother than you did. I believe that she was a devoted mother to her son, but that her son gave into evil. Perhaps if they had raised their children with some religion — beyond a few visits over a couple of years to a Lutheran church — her son would have resisted evil, but who knows? The book Columbine by Dave Cullen was superb. I recommend it. It puts the blame where it belongs: on the shoulders of the shooters themselves.
My problem with her is that she refuses to admit any of the warning signs that she saw. She ignored them, and then she tries to make it sound like ignoring the warning signs wasn’t her fault either.
She poo poo’s them away as if they were a fly that landed on her cupcake.