I could rewrite the quote in bold, about religion:
some people hold truth as self-evident
and then proceed directly to religious endeavor.
and what followed was obviously not true
You can believe anything if you rationalise it and then turn stubborn about it.
That can apply to any religious person, especially if you are a creationist.
I think you are confusing truth with fact.
Truth, whether it be in religion or in philosophy, is very subjective, very much like personal opinion/view or belief, where a person's ego and bias can influence how they think or reason to reach the conclusion.
I like logic, but only if the logic is accompanied with evidences. The problem with philosophy is they tend to rationalise, and oversimplified what they call "truth".
If you want to be objective or impartial, then you have to remove one's bias out of equation, by relying on testable or verifiable evidences to reach the conclusions. That's fact, not truth.