That is an interesting point. I will raise a couple counterpoints to it:
- Given that dark matter and normal fermionic matter don't seem to interact, I think that the way that non-antimatter came to be dominant would not necessarily apply, particularly if dark matter is primordial or all formed very early in the Big Bang. Normal matter would then go on to satisfy the Sakharov criteria and become unbalanced, but dark matter would never have satisfied the Sakharov criteria and thus would be balanced.
- Dark antimatter could be rare, but in the more concentrated environment of the galactic center, more likely to find dark matter to annihilate with. Remember also that unlike the mostly charged fermionic particles of normal matter, dark matter doesn't have many if any charges, so there wouldn't be attraction between dark matter and dark antimatter like there generally is between a normal matter particle and its antiparticle. Thus, only in places where there was a concentration would dark matter and dark antimatter be likely to collide and annihilate.
And nothing says that both of these cannot be true.
I'm not sure I understand what the first account is, nor how dark matter at lower concentrations in the galactic disk and halo not interacting precludes dark matter in the galactic center interacting. I think that needs a bit more explanation from you to detail precisely what you believe is contradictory.
Fritz Zwicky is generally credited with discovering dark matter in 1933, and
Jacobus Kapteyn and Jan Oort with coming up with the idea in the first place, though Oort's hypothesis was not well supported by the data. I had to look Vera Rubin up. She was 5 years old when Zwicky published. I'm going with Zwicky's anomalous rotation being used to predict the existence of dark matter in the first place.
If dark matter interacts with normal matter through the gravity force, then it is reasonable to assume it is also acted on; thus, one would expect to find more dark matter in the galactic center just as, and for the same reasons as, one finds more normal matter in the galactic center.
It's good to be skeptical; we can't all have the same opinions or there'd be nothing to talk about. However, dark matter is not an "outrageous speculative claim." It is well-founded and based on gravity theory; the only assumption is that galaxies out there follow the same rules of gravity as everything on Earth does, and since we make that assumption for everything else in physics, it seems to me rather inconsistent to fail to make it for gravity.
As far as BICEP2's initial reporting, and later retraction, of the claim to have found the signature of gravity waves in B-mode polarization of the CMB, the problem with it was caused by interstellar dust in our own galaxy, which they used the best available data at the time to estimate. That data turned out to be wrong, as shown by the Planck data set, and they promptly retracted when this new data became available. Neither faulty instrumentation, nor misuse of instrumentation, had anything to do with it. Nor did they behave like unruly children.
