How is the visit from the Clybourne Park Orientation (or welcoming) Committee ironic? What reasons does Lindner give to support their proposal? Act 2 Scene 3

The "welcome committee" wants the Youngers to actually move out of the neighborhood. They are willing to buy the house to keep black families out. Lindner uses the excuse of a recent incident of a bombing after a black family moved into a white neighborhood. In order to prevent this sort of "deplorable" event, Lindner thinks the Youngers should move out for their safety.