What follows may seem a "technical point," but it really isn't. During the Creed, we all stand and profess "...I believe in One, Holy, Catholic and Apostolic..." That "Oneness" is "Unity" and that unity is a unity of Worship, Doctrine and Authority. (Vatican Two, in Lumen Gentium if I remember correctly,has the same explication of what is necessary to be Catholic)When one stands and professes the Creed while rejecting Doctrine, he is professing a lie. By rejecting Doctrine he is declaring he is not a Catholic.
It is easy to see that any "Catholic" who rejects Doctrine really is not a Catholic. He may profess publicly he is; but he is lying. He may answer polls intending to survey Catholics but his answers are invalid because he is not Catholic.
I don' think I have EVER seen a poll that surveys Catholics qua Catholics. When one hears a "Catholic" opposing Doctrine, remind yourself you are listening to a non- Catholic.
It really is the same thing.....