Is it just me or did I miss the part where it denies the infallible doctrine of BOB/D.
Yes, you clearly missed it, because you obviously have zero theological training and have not even the slightest competence to discuss such matters, much less to be blogging about them online.
The implications of the quote are obvious, if you can speak English and have basic analytical skills.
Vatican I is saying that supernatural faith (as opposed to natural knowledge) REQUIRES (by definition) a supernatural object, i.e. one which can ONLY be known by revelation. This rules out saying that it's sufficient for supernatural faith to believe in a truth that can be known by natural reason (i.e. the existence of a rewarder God).