A couple of old bones which cause a revision of an evolutionary timeline model (about which species coexisted with which others when) do not “cast doubt on the theory of human evolution”.
All this discovery may mean is that instead of homo habilis being the ancestor of homo erectus the two species may share a common ancestor instead. This casts no doubt on the theory of human evolution itself, merely upon the way the branches of evolutionary adaptations that led to homo sapiens occurred. Refining a model to take account of new data is not the same as throwing away the entire theoretical framework.
Is a little, tiny, bit of scientific literacy too much to ask for?