[throwawaymaths]

It falls under "don't treat science like a bunch of gotchas". There's a lot of shit we don't know. There's a reasonable argument that the observed lensing might be refractive index distortions from increased gas density in the bow shocks, aka, "actual lensing".

[dataflow]

Okay, but if it's even questionable at predicting that, why then does everyone keep saying that dark matter is such a great explanation of a million phenomena and their grandmothers and especially the Bullet cluster? I thought that was supposed to be one of the things that gave the theory widespread legitimacy and now I'm hearing that I've been basically hearing fake news this whole time? I'm really confused.

[throwawaymaths]

Scientists are bad at their job? I don't know.

I remember in ninth grade physics class we did an experiment where we measured gravity and used excel to do an R^2 fit on the parabola to a second order plot. One very smart (not being sarcastic) student discovered that she could get a perfect fit with a seventh order equation (we had seven data points). I did not have the vocabulary to explain to her why she was wrong. She now sells healing crystals. Sure, the fit explained more things, but it was not a good model. Explaining a million things is not powerful when each thing you explain has a unique parametrization that you can use to "get it to work".

Mond predicted something called the external field effect, a researcher went looking for evidence it wasn't there, and then changed his mind when the evidence showed there was an efe. So there are at least some good scientists out there.