First, what we are talking about is the papal bull Romanus Pontifex issued in 1455.
The Romanus Pontifex was a specific papal bull. It pertained to the ongoing wars (counteroffensives) against pagan and Muslim kingdoms. At the time, Muslim armies were still marching across Europe and the church was on a 400 year streak of bringing relative peace to Eastern and Northern Europe via the conversion of pagans, such as the Vikings. Monarchy was also the accepted form of government at the time, meaning that any given peoples were not complete until they were ruled by one.
There is no more reason to resend this bull than there is for Britain to denounce the Magna Carta for its failure to protect the individual rights of homosexual peasants. The church also coronated kings, should they rescind all of those coronations, because we no longer accept monarchy as a valid form of government?
This historical tail chasing is simply a passive aggressive attack. The current positions of the Catholic Church are well known. If someone has a beef with them, that would at least be pertinent.
The world was a very different place in 1455 and its not helpful to pretend that it wasn't. The Romanus Pontifex was not drafted in a vacuum, and it shouldn't be readdressed in a vacuum without context. Reopening all of that "context" would likely do far more harm, than any good that could be achieved.
So, in other words there is no reason to not rescind this other than you find it annoying.