A Protestant believes in no infallible authority; he is an authority unto himself, which authority he does not claim to be infallible, if he is sober and sane. He is after truth; and whatever he finds, and wherever he finds it, he subjects it to his own private judgment. He is free to accept or reject, as he pleases. He is not, cannot be, absolutely certain that what he holds is true; he thinks it is. He may discover to-day that yesterday's truths are not truths at all.
Do you have a source for that ditty, or did it come out of your own thought patterns? As for the anti-Protestant content, I would say whoever wrote it has a false understanding of how we think. Had the RCC stayed faithful to the authority of the Divinely-inspired Scriptures - as was voiced by most of the ECF - , there may not have even been a need for the Reformation. But God STILL works in the hearts of man.