The dark matter is misnomer - it's colloquial denomination of quite diverse range of phenomena, which may or may not have something to do with matter concept as we know it. In perspective of dense aether model, every steady-state fluctuation of vacuum or curvature of space-time can and should be considered as a matter already, as it should have reference frame assigned, speed, velocity and also gravitational and inertial behavior assigned.
Therefore in my understanding, the dark matter really IS a matter - except that the majority of it remains formed with extremely volatile and short-leaving density fluctuations of vacuum, which are on the verge of virtual particles and quasiparticles, rather than quasiparticles and resonances. But as a whole these temporary and sparse fluctuations have the similar material behavior (lensing and inertia), like finely divided particles of real matter. These "particles" are just way more lightweight, than the mainstream physics expected so far. The reason of this stance is, the mainstream physicists cannot imagine the gravitational lensing of dark matter without breaking of equivalence principle of general relativity and without presence of some massive particles - so they they obstinately searched for quite heavy particles first WIMPs and gradually it decreased the upper limit of their mass (SIMPs).
Currently the physicists have (nearly) nowhere to go with this approach already, because the lower limit of their speculations represents the neutrino background, the noise of which prohibits further increase of sensitivity of dark matter detectors. A precarious situation, isn't it true?
The authors of modifications of general relativity (MONS, MOD, TeVeS and MOND) together with Cartan-Evans theory believe, they can derive the main aspects of dark matter behavior without consideration of some material background at all. But they have no chance with it anyway, until they want to preserve the equivalence principle - just because the dark matter has been originally recognized by its equivalence principle violation. Therefore the violation of equivalence principle and fundamental general relativity equations is the only way where to go.
