Your whole premise is based on the fact that you can't disprove a negative. As a wise man once pointed out "Throughout history, every mystery ever solved has turned out to be NOT MAGIC." As another one pointed out, religion is being dwindled to the point of being known as "the god of the gaps".
Nope. My premise is about rationality. Simply, just because somebody has a different rationale for doing something to you doesn't make them irrational. If they have an internally logical reason for doing something then it's still rational, according to the dictionary definition of the term.
In order to be rational, you simply need to be capable of reason. You don't need to come to the same end result.
Imagine the following situation. Somebody comes across an opportunity that would be extremely advantageous for the individual, at the cost of breaking a rule, but with zero possibility of getting caught.
A non religious person might rationally consider they stand no chance of getting caught and is more likely to take the opportunity, knowing that they won't get caught.
A religious person who actually believes in an omnipotent all knowing, all seeing God might decide that while they wouldn't get caught by any mortal on this plane of existence that their God would know and might/would punish them on this plane of existence, or worse on the next plane of existence by refusing them entry to heaven and letting them burn in hell for all of eternity. Upon that basis, the purely rational basis of "is it worth it" skews the possibility of getting caught from "not a chance in hell" to "it's a certainty that I will end up in hell". Hence, that skews the result of a logical calculation of risk and the outcome might look like:-
1) Non religious person takes the opportunity.
2) Religious person does not take the opportunity.
And both people would be making rational decisions, in that they have logically considered the situation and made a decision on the basis of that.
Although you can consider and evaluate an idea without agreeing with it, you're ability to consider and evaluate it fairly drop away dramatically.
Personally, I evaluate an idea first and then decide if I agree with it or not based on that evaluation. Only an utterly irrational bigoted fanatic could possibly decide if they agree or disagree with an idea before actually considering it?