water baptism is a picture of death, burial and resurrection (coming up out of the water).
Why bother baptizing bringing them up out of the water if Christ is one of the collective dead (singular - "the dead ones") and HE did not resurrect from the grave?
Paul clearly doesn't ascribe baptism for the dead to the Corinthian church, so it's clearly wrong for anyone to declare anything to the contrary. It's too bad that some people don't want to get a clue even when it's spelled out that Paul didn't say "You baptize" but that "[Some] people baptize..." If the Corinthian church did it, Paul would have said "You", or "We" (if it were a Christian practice). How is this too difficult for anyone to understand (to barrow a phrase from Dave)?
It's nothing that any apostles would have taught the church of Corinth to do. It's nothing from scripture. It's nothing that Paul would implicitly approve of, as would be the case if the Corinthian church were doing it. And, arguing that the church baptized the dead when they didn't believe in the resurrection is a stupid argument, precisely because baptism for the dead implies a resurrection.
So, the Mormon church and others who think the Bible teaches baptism for the dead are dead WRONG.