What is common between the chrysalids compared to World War 2?

Well....

The mutants in the chrysalids were driven out of Waknuk into the Fringes because of their appearance in which there was a large chance they could die. This shows that the people of Waknuk basically wanted to drive anything that they thought was not "Pure" or "Right" simply out of their living area.

Similar to this, the Natzis did the same thing during World War II to the Jews, although this was not mainly due to their appearance. The case during World War II was a bit more extreme though seeing as the Natzis were killing the Jews because it was their belief that they should not be part of the population, just like the people of Waknuk think about the deviations and mutants in 'The Chrysalids'

All in all, both events are similar to each other because they both encounter a population or leading group that does not approve of a certain feature on a person, weather its physical or not, and they try to drive them out of their lives.