Agreed. And I also see no reason why the Confiteor be left out period each week by a number of priests where I (occasionally) attend the N.O.
Or, is there a reason many will do this?
The excuse they'll give you: the responses of "Lord have mercy, Christ have mercy, Lord have mercy" adequately express penitence and therefore the Confiteor is unnecessary.
And instead of the Preface, I should have said the Sanctus. Perhaps both.