> If you "solve racism", then redlining and white flight still exist?

I think he means that it will be replaced by something else and the end results will be the same. A lot of problems we attribute to racism will be there due to some other cause. Problems have multiple sources, and solving one will not solve the problem. A common debate in society is precisely about how much of a given problem is due to racism. Some people assume it's very high, and others say it is just one amongst many.