There are a few interpretations that I have come across regarding the specific meaning of this verse, but all agree that this is a small argument in a wider context, not a change of direction from the verses before and after it:
John Stevenson (a Presbyterian theologian) argues that "for" in this case means "in the place of". This was a time when Chrisitans were heavily persecuted and frequently killed, yet the gospel message was spreading and more believers were being baptised. So Stevenson asserts that this verse is asking (rhetorically), "why, when so many Christians are being killed for their faith, are people still becoming Christians and being baptised, replacing those who were killed?"
Meanwhile, Matt Slick of the Christian Apologetics and Research Ministry concentrates on the meaning of the word "they" as opposed to "we". He asserts that Paul is talking not about Christians, but about a pagan religion from Eleusis, north of Corinth, who believed that baptising in the sea guaranteed a good afterlife. Slick's interpretation is that Paul is saying "if even the pagans believe in the resurrection and the importance of baptism, why can't you?"
The Restored Church of God teaches that the word "for" should be translated as "in the hope of" and asserts that the meaning is much more straightforward: if there is no bodily resurrection, we have no hope after we die. We therefore believe and are baptised because we do have hope that the dead will rise again.
While these interpretations vary in their conclusions regarding what Paul was specifically referring to, they all make the point that the verse must be taken in context. Stevenson explains,
The context of this passage is one in which Paul is arguing on behalf
of the doctrine of the bodily resurrection. The Greeks as a rule did
not hold to a bodily resurrection. It was a new concept to them. Their
religion taught that the afterlife consisted of a disembodied
existence. Throughout this chapter, Paul gives one argument after
another showing that Christians legitimately believe in a
So the verse itself doesn't result in specific doctrines in protestant churches outside of LDS, because the verse is part of a much wider set of arguments for the doctrines of baptism and the bodily resurrection.
I've picked on a few particular resources that address this issue but there are several others that also support the argument that the verse should be taken in the context described above and not as an indication of support for baptism on behalf of those that have already died. In addition, here's a specific rebuttal of the Mormon view from David Pratte's gospelway.com website.