Well, I didn’t literally mean there’d be just a single place. Obviously, once you set that precedent, other places like it would start popping up too. But it’s not obvious to me that this is a bad thing - or at least worse than the alternatives. I don’t think there’s anything inherently wrong with people wanting to live among like-minded people and, in effect, build echo chambers for themselves.
I do think the philosophy behind it is immoral from my perspective, but that’s not really the point. What matters is the concrete effect this ideology has in the real world. And if, in our current cities, we have racists committing racist violence against minorities, then is it really so much worse to just let them all move off into their own little enclave where they can live out their perfect lives without any black people around, if that’s what they want? At least then the rest of us wouldn’t have to deal with them on a daily basis.
Which, lets not forget, may very well be true. Wishing it to not be true is wishing that a child got raped only because the consequences of that would further one's political agenda.