Dystopian, yes -- but surely some form of implied apocalypse must have happened for their drastic scenarios to have come about. So in that sense they could be argued as being post-apocalyptic, if not apocalyptic in themselves.
Unless instead of a big-bang type of apocalypse there was a progressive (but none the less damaging) slide into the dystopian future they portray; which is where "Camp of the Saints" comes in, as an examination of the psychological interactions, delusions, wishful-thinking and assumptions which could allow such futures to develop. It is indeed politically incorrect in that it portrays a possible end result of political correctness having been carried to its logical conclusion, but then running aground on harsh reality.