This is a good explanation because it gets at the source. L. Ron was a failed Freudian and had some mental issues of his own, he lashed out at the psychiatry community, and built this whole thing out of a hatred for what (rightfully) rejected him. He just happened to write shitty sci-fi, so he channeled that into pseudo-psychiatry (Dianetics). There’s a reason those e-meters exist: bullshit stress response devices to measure “clearing” certain negative thoughts. They don’t actually work, but that’s the principle: you have a “auditing session,” and let’s say you get asked about your propensity for lying in a certain situation. E-meter response is measured until you’re no longer stressed by the thing you were asked about (according to the meter), you pay them absurd amounts of money, they now have dirt on you in case you try to leave, etc. This is its core, reductively. Anti-psychiatry money mill.
He would’ve been fine at 374, but it was that last one that was just too much.