While I would agree with your points on the 10,000 added to London's population, almost all requiring immediate assistance of one type or another, which will create a large amount of stress on the system. The  number is not large in relation to London's population but added to London's homeless population is where the impact would take place. We are dealing with human beings here and we are all, in one way or another, creatures of habit. I agree that people must confront their bigotries but that will only work if done slowly, over time. It will cause anxiety and stress if made to deal with it instantly, or what seems to be instantly which will result in things like the Brexit vote and no telling what else.