First, thanks for another interesting (to me) essay.

People have been confusing "reason" and "rationality" since the so-called 'Enlightenment'. See, for instance, the third (single-sentence) paragraph and the first sentence of the eighth paragraph in the essay at hand

As noted in the essay, 'reason' is basically a synonym for 'being logical'. Not noted: rationality refers to the consistency of an abstract position (proposition, assertion, etc.) with 'what is true'.

We can reason from any starting point, including purely personal truths such as whether we 'believe in God' or not--or whether we believe in the 'equality' of all people or believe in some kind of inherent hierarchy. Accepting such truths happens extra-rationally. No one can really explain why one has accepted as true any purported truth of an immaterial kind.

The (perceived) experience of material existence provides starting points that are not purely personal, but refer to phenomena physically external to any person. It is possible for such experiences to be restricted to people with specialized knowledge, such as scientists. Some material phenomena are experienced by all people.

Spiritual phenomena can also be external to a person (having experienced such myself), but they are not experienced by other people in the way that material phenomena are (or at least can be). Accepting as true or rejecting the truth of such phenomena is, again, a purely personal matter.

It cannot be irrational to reject any immaterial truth, but it is irrational to reject a truth about material existence. Being irrational concerning some truths about material existence will not adversely affect anyone, but being irrational about such truths can definitely be the path to material disaster--with the emerging climate crisis as one example. If nothing else--much like 'Pascal's bet'?--erring on the side of caution is advisable.