Question...If God honors the posthumous "baptisms", why would Catholics want to oppose God. If he does not honor these "baptisms", why should Catholics care what Mormons do?
The third Mormon "prophet" John Taylor--the same person who was in jail with Joseph Smith on charges of vandalizing/detroying a printing press...the same person who said that the LDS church would never backtrack on polygamy despite up to 1300 men being jailed in the years during (or surrounding) his Mormon presidency...also said:
"...we are the only people that know how to save our progenitors, how to save ourselves, and how to save our posterity in the celestial kingdom of God;...we in fact are the saviours of the world..." (Journal of Discourses, vol.6, p.163).
Of course, what Taylor was referencing was the ritual practicing of baptizing dead folks. (LDS even conjure up a vision of LDS priestholders going over on the other side & assisting with folks receiving the perverted Mormon gospel).
So I ask: Why would the Catholic church want to continue a practice that only continues to elevate Mormons in their own minds as "the saviours of the world?" (This is, pure & simple, idolatry to place themselves in the lone Savior role reserved for Jesus Christ).
As the book of Revelation makes it clear: Only "One" slain-One Redeemer (Rev. 5:9) was "worthy" to open the scrolls; there's only ONE Lamb of God who takes away the sin of the world.
If proxy baptism would have been the route to world salvation, he would have done it himself. But he didn't. In fact, he rarely even baptized any living person:
I am thankful that I did not baptize any of you except Crispus and Gaius, so no one can say that you were baptized into my name. (Yes, I also baptized the household of Stephanas; beyond that, I don't remember if I baptized anyone else.) For Christ did not send me to baptize, but to preach the gospel—not with words of human wisdom, lest the cross of Christ be emptied of its power. Christ the Wisdom and Power of God. For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God. (1 Cor. 1:14-18)
And that's what is telling...no crosses on Mormon facilities...But proxy baptism tanks in their temples...Ones that could be utilized 24/7 in dozens of temples if only the Mormon claim that the apostle John is still alive would come forward with all the names of the dead that you would think he'd have access to with a 2,000 year lifespan...but no...(same about 3 supposed ancient Nephite disciples still walking the earth)...but I guess proxy baptism just isn't a priority to them...)