Notice what I said: to limit Jews to ghettoes. Voluntary segregation and creating Jewish areas to attract Jews does not limit Jews to ghettoes. In general, creating ghettoes to benefit Jews is not a reason to limit them to ghettoes. Furthermore, since I was using ghettoes as a counterexample, even if I had not phrased it that way voluntary segregation still wouldn't count, because in order to have a counterexample it only need be true that some ghettoes were created to harm Jews, even if others were not.
have a counterexample
Azathoth123 said that people generally don't build fences to gratuitously cause harm, not that they never ever do.
Another month, another rationality quotes thread. The rules are: