@UJM, there is no reason to worry about there silly second coming beliefs. The problem is that this causes them to believe in the importance of missionizing to Jews, which is worse than physical death.
At the same time, we do applaud their adherence to the sheva mitzvos, as the Rambam writes (הלכות מלכים פי”א ה”ד) that the purpose of Christianity and Islam was to prepare the אומות העולם for Moshiach through teaching them about G-d, the Bible, and the idea of G-d commanding us how to behave.
At the same time, he writes, they have a completely warped version of religion, and “there is no greater stumbling block than this”, and when Moshiach comes they will come to realize how much they erred.