As he comments, his posts show a clear disagreement with the scientific method. That, not the truth of quantum mechanics, is a basic part of what this community calls rationality.

Later in this sequence, Eliezer asserts that QM represents a failure of science to be as rational as it could be. The example can't be understood unless one has a fairly good grasp of QM, but the truth of QM is not precisely the point of this particular series of essays.

(As an aside, I'm not completely convinced of the point because I think the example is poor, but that also is unrelated to the truth of quantum mechanics).