Well I mean what's going on is plainly a state responsibility and not the federal government's. Obama and Holder should be threatening Nixon with whatever they can, but I don't understand why criticism would be placed with them and not the people whose actual job it is to oversee local governments in MO.
Federalism is a wonderfully flexible system of government. It would be ideal if the Governor put on his big boy pants and sorted things out but its far from unprecedented for the Federal government to intervene when racial tensions explode into multiple day protests and police response.