This is no Chabad invention, it's an integral part of Judaism and part of the 13 principals of faith codified by Maimonides. Those who are put off by the Messianism of Chabad need to check their Jewish sources and find whether it is Chabad that puts them off or something that is endemic to Judaism itself. The problem is not messianism per se. The problem is with those who persist in calling Schneerson the messiah after his death. Jewish sources are pretty clearly opposed to the notion of a dead messiah.