He would be right _IF_, and only _IF there was a qualifier next to the use of "exponential" (As I originally stated). Unqualified, it is a psychological trick because your mind will automatically associate the provided "annual" qualifier to the term.
That is not to say you can't stop and rationalize it correctly, but that you have to stop to rationalize it to correct it makes it classic brainwashing ala Bernays and his ilk.
Exponential is an absolute term. It doesn't need a qualifier, if the formula fits it's exponential.