Quite a bold statement. I'm almost sure I've read about numerous neutron stars being observed in different electromagnetic spectrums(possibly not in visible light, I'd imagine). Correct me if I'm wrong.
What about pulsars...as I've said above - potentially every neutron star is a 'pulsar'.
Current scientific dogma dictate any high energy point source emission in space MUST be either; Neutron stars, Black holes, Quasars, Neutron binary's, Oh and I even now hear of the newly idea of a "quark star", It's also fitting that all of these objects can never actually be experimented with, We just tag anything in the sky one of the former names depending on the type of radiation.
Perhaps they should start making vacuum tubes and realize you can make X-rays with some cello tape, it might change their minds on exactly what these objects are...