Urban centers don’t need to be assaulted. Just closed off and put under siege.
Soy boys and spoiled white girls would surrender and flee once food started getting scarce.
Only the tougher and strongest would remain. As long as you don’t let them out, or anything in, you won’t have anything to worry about.
So what happens to the soy boys and and spoiled white girls when they come out? Prison? Shot on sight?