That's a fair stance, so long as you also agree that dual citizens should be allowed to work in government service if they relinquish their foreign citizenship beforehand.
If that's an unacceptable compromise, you're going to need to bring back McCarthyism era purity tests, because treason still occurs even amongst natural born citizens.
Though, I'm not necessarily against the return of McCarthyism era purity tests either, even as a dual citizen.