I am not sure about SS comparision. JW believes that the their G-d and his angels will do the mass killing and batches like in Babi Yar, and they will just idle by signing hoshana. In my hometown during WWII, Germans were killing Jews and partisans on the outskirt of the city where they had orchestra playing music, while the slaugher went on. JWs would be these musicians.
However, if the cult leader told them to kill themselves, they would. They would follow their leader. They want to suffer martyrdom in the name of the WT and many will not hesitate to kill themselves for the truth. They wasted their life for WT, they would end their life for lie of WT.