What makes people irrational thinkers?

[Oldandeasilyconfused]

That it collapsed at that time is clearly due to witchcraft"

Does Evans-Pritchard pass judgment on whether these people are "irrational thinkers" or not?

It seems to me that if a person grows up in a culture in which witchcraft is a typical explanation, then believing in it is not irrational. Internally self-consistent belief systems which form the basic metaphysics of your society are just things that rational people are likely to accept. 

So if someone in a witchcraft metaphysics culture confronts something inexplicable, they assume it must have a witchcraft-based explanation. And if someone in a materialist metaphysics culture confronts something inexplicable, they will strongly believe that any explanation must be materialist -- or else insist that asking for an explanation is somehow invalid. 

I'm reluctant to say that people from other cultures are irrational, just because they think differently than my culture.

"Does Evans-Pritchard pass judgment on whether these people are "irrational thinkers" or not?"

Not as far as I remember, but it's nearly 40 years since I read any of E P's work. I'm basing my comments on what I was taught at university. 

 Anthropologists do not usually pass judgement.  Their task is to learn the meanings within a culture. They are as objective as they can be in the circumstances.