I don't consider him a rationalist character. He is always hung up about what is logical, as opposed to what is observably right.
Uhura: Mr. Spock, sometimes I think if I hear that word "frequency" again, I'll cry.
Spock: It is illogical for a communications officer to resent the word "frequency."
What kind of answer is that? "Too bad you dislike your job?" A rationalist answer would have been something along the lines of "Can you explain why, maybe we can find out what went wrong with your feelings and find a way to fix them or work them around?"
There is a difference between rationality and smartassery.
What kind of answer is that?
One that, presumably, would make Uhura cry.
Hopefully at least one or two would show a virtue of non-straw rationality.
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