Certainly that is true.
I just don't see Baptists, Lutherans, Presbyterians, etc. releasing position papers that claim the Roman Catholics or any other denomination for that matter don't sufficiently have the REAL "truth" of Christianity.
Maybe they did recently, and I missed it.
That RCC claim of superiority just smacks of intolerance, pure and simple.
And if one can't see that, they are blinding themselves to reality.
PS -- and just so no one accuses me of Catholic bashing, I will say again that I dearly love my Catholic brothers in Christ, and admire and adore all the transformational good they've done in the souls of men and women.
It's not only the RCC that claims to be the one and only true church, but the eastern orthodox, do as well.
Did I mention the Mormons do too?
Well, relativism by definition reject absolute truth. And Porestantism is founded on relativism. The Protestants themselves can't agree on anything because every Prtestant believes something different and claims his personal belief to be the real truth while assailing "traditions of men."
Try the Westminster Confession of Faith which calls the Pope the antichrist.
There are a few other post Reformation position papers which explicitly instruct.