Your premise is flawed, in that it says one must allow an unsupported argument to automatically receive undeserved credence because if someone challenges its validity, it wins legitimacy simply by being refuted.
Using this logic, if someone claimed the moon might be made of cheese so it should be taught as an alternate theory, and someone else opposed teaching this on the basis that it is a ridiculous claim without merit, then would the very act of opposing the Cheese Moon Theorytm make the notion that the moon is made of rock 'suspect'?
Your usage of the moon is not relevant as we have proof of what the moon is.
To evolutionists anyone that questions that theory is suspect, there is no allowance given that the theory is questionable. Evolutionists fit the profile of survival of the fittest as they believe the wholly own the answers.
Evolutionist find, claim, and profess evidence for what they claim to be common descent all hindged upon one theme God had no part in it.