It depends how you define "don't believe". They might say they don't believe in evolution, but that doesn't mean they act in ways that are logically congruent with evolution being false.
"Most people don't act in ways that are logically congruent with all their beliefs."
Do they really believe them then? Is there any reason not to say that a belief, by definition, is something (among other things) that you act logically consistently with.
I'm sure there's a word you can define as something that you act logically consistent with, but I think it's closer to the word "motivation" than the word "belief".
If somebody says "evolution is a lie, and it shouldn't be taught to children", the fact that they don't actually live their life according to that credo is sort of irrelevant.
