The reasoning for some of these questions is that if you are caught, it’s sometimes easier to charge you with fraud (lying on the form) than the actual thing (such as espionage).
Maybe to deport you for espionage requires a jury trial, but to revoke status for misleading answers on an immigration form is administrative and so is deportation for lack of status.
I seem to recall some extraordinary cases where untruthful answers on immigration forms were used to justify denaturalization.