Agreed. But we have to keep in mind that this is how science works. For example, if were strict, we could not say "there is an exoplanet orbiting that star", we

Agreed. But we have to keep in mind that this is how science works. For example, if were strict, we could not say "there is an exoplanet orbiting that star", we could only say "there are a bunch of observations that make it seem as if there is an exoplanet orbiting that star". And if you take this to the extreme, we do not know if the star is there. It is the same for laws: nobody has observed gravity or GR, just their effects. We can get philosophic and wonder if we are here... At some point, we have to assume that observations correspond to an external reality or everything gets meta. While I agree that it may be convenient to make more clear what we know about dark matter, it is not easy to find the perfect name and, it seems to me, not a task for physicist, who just need a name for the terms in their equations.