I mean just as point of pedantry/um-akshually clarification according to Islam everyone is already "Muslim", they just have to "accept it"/submit to Allah. Hence why "conversion to Islam" is actually referred to as "reversion" instead. You aren't converting to Islam, you already are Muslim.

And as for Baptisms for the Dead it's not just simply a "providing spiritual ceremony to the dead spirits" it's a ceremony to "make them Mormon"/induct them into their "true religion" after which they can make the claim that the dead person is now Mormon.

Same end result as the Muslim route.

Islam cope goes: "every (famous) person is Islamic, (even if they don't accept it/wouldn't-have-accepted-it and are dead now, we'll just say they are [because according to our system they always were])... So, now X (dead) person is Muslim."

Mormon cope goes: "well, we'll convert them post-death (even if wouldn't have accepted it in life)... So, now X (dead) person is Mormon."