This was the craziest thing to me. I spent a large part of my childhood in Oklahoma, and all of that was either in Tulsa or its suburbs, or at least in Tulsa’s gravity well as the closest major metro. I didn’t learn about this until I was almost 30. It boggled my mind to know that something horrible like that happened just a few miles from where I lived and I never knew. I think there’s a museum now, but I can’t for the life of me recall having heard of it when I lived there, so I think it may be recent-ish.
Could also be a politically smart strategy. Basically, with no public court record or court reporters to share the prosecution’s case or present the evidence, you can always come back later and say “the crooked deep state made me plead guilty because they knew they didn’t have a case and they needed me out of their way!”