Is there really anybody suggesting that we put _Diplodocus_ back into the swamps, or has somebody who's got no clue what they are talking about edited this bit into Wiki?
Neither nor. The idea that some sauropods were sort of semiaquatic or at least stood on river banks and ate water plants cropped up occasionally in the early 1990s or so. It's dead, however, and I'll erase it from Wikipedia if you don't beat me to it.
Also, everyone, please stop calling Wikipedia "Wiki". Wikipedia is one wiki out of thousands. :-)