One of the reasons some do this is because they MUST remain convinced they are in the "right" church, jumping the right hoops, doing the right rituals and praying the right prayers in order to somehow have hope that maybe, just maybe, they might make it to heaven when all is said and done. They cannot countenance that worldview being rocked even IF everything you have said is verifiable and true - they won't take that chance. And for some others, this one point - the Papacy in Scripture (which we can see well enough is fantasized as being there) - gives them the assurance that therefore EVERYTHING else this "Church" says must also be the truth. IF they can convince an undecided that the Roman Catholic Church IS the one Jesus set up headed by Peter, they can get their foot jambed in the door enough to slip in all the other developed, contrived, invented and perverted doctrines thought up over the many years since then and make acceptance of them mandatory.
The thought that comforts me through all this is knowing that God is a rewarder of all those who diligently seek HIM. Those looking for a religion or church they can boast about or which helps them to feel good about themselves and what they do, will probably not be the ones doing the seeking of the truth. That road to heaven is narrow - and few there be that find it.
Bless the Lord for what helps. It does seem RCs must be getting an indulgence for posting reposting refuted RC apologetics. Maybe to use up our time.