I just got to thinking about this issue last night.
Regular followers of the news know that Mormons have been in dutch recently for some particularly egregious practicing of their doctrine of baptism for the dead, namely, living Mormons being baptized for Anne Frank and other dead Jewish Holocaust victims. (That said, with Mormon temples around the world, and splinter Mormon sects to boot, it's surely still being done somewhere.)
That said, if Mormons are getting attacked not just for what seems a tad morally repugnant, but for the entire dogma of baptism for the dead, others might not want to pick up stones.
Rick Santorum's Catholic church, for example, believes in prayers, to saints as well as to God himself, on behalf of those in purgatory. Jack Kennedy, in 1960, had concerns raised over whether he might put the pope and the Vatican ahead of the U.S. Interestingly, though, nobody asked him about weird dogmas like this.
And trust me, I can find others in other religions, but the Catholic one stood out because it too is for the dead.