It does seem unfair to fault one theory for making up terms but to ok the invention of dark matter and its placement wherever needed. Perhaps dark matter will be like vulcan: a big chunk of mass invented and placed so as to confirm an outdated model. The new model described a new force, mooting the need for the mass.
It's faulting one theory for making up terms to fit one source of data and then those same terms failing on 6+ other experiments. Dark matter's predictions are consistent across totally different experiments with fewer sets of parameters.
