L. Ron Hubbard was psychiatrically ill, he did evil but it's not clear how far he was
Yet, Hubbard was dubbed "schizophrenic and paranoid" by a California Superior Court judge, and Scientology dismissed as "immoral and socially obnoxious" by a High Court judge in London. [1]
Now, decades after Hubbard's death it may be difficult to determine how far Scientology was psychotic delusion and how far deliberate fraud but Scientology isn't rationally believable.