The problem with that the plaintiff had who's name was Oliver Brown was that his 8 year old daughter couldn't get into school because she was colored. So he went to court to have segregation put to an end in the public schools.
One of the things that gentrification represents is that there is an influx of newly wealthy people that exist as a result of a growing class divide.
So, the hope is that people will stay where they historically grew up and improve that area as opposed to moving out and spreading out.
Either way, the root issue is a growing class divide.
Isolationist Republicans were mainly opposed to the lend lease act of 1941.