"It's not pejorative. It's literally true. Whatever it is, it does not couple to electromagnetism; it cannot radiate or absorb light. It's not just a matter of a higher or lower frequency. The only handle we have on it (indeed, the only one we can have) is gravity. That's how it was first inferred, and that's how this map was made."
It is pejorative, because "light" and "dark" carry, in all human cultures, weighted values that goe beyond, and even long precede the mundane scientific knowledge and understanding of the properties of phontonic and other energy wavelengths.
"Dark" while scientifically meaning that our human photonic receptors do not receive photon input from something, carries a deeper meaning, culturally as "dark" places are dangerous or, at a minimum at least pose some level of risk and at a maximum are "evil", bad and everything opposite of "good" (which is associated with light). Thus "dark" always carries a subjectively pejoritive value.
To say that "dark" matter does not "absorb" "light" is an error, for we do not really know that. In fact it may "absorb" light so thoroughly, as part of the attributes whereby it seems to not radiate or reflect light.
It would be more accurate and less pejoritive if the missing matter was referred to simply as "hidden"; hidden from we who do not yet have the eyes, technical or otherwise, to "see" it.
And "heavy" means "fat" to many laymen, so that's pejorative, too; perhaps we should say the top quark is "big boned". What are you trying to protect against? Scientists know what is meant by "dark". If some laymen think it means "evil", what of it?
To say that "dark" matter does not "absorb" "light" is an error, for we do not really know that.
We absolutely do know that. Absorption is as easy to detect as emission. Simply measure the spectrum of light from more distant sources, and see what's missing. (Google the term "Lyman Alpha Forest" for a wealth of details.)
Indeed, our ability to measure precisely all of the intervening baryonic matter (i.e., matter made of protons and neutrons) provided one of the clues that revealed the existence of dark matter in the first place: there was nowhere near enough absorption to account for the observed gravitational lensing effects.
In fact it may "absorb" light so thoroughly, as part of the attributes whereby it seems to not radiate or reflect light.
So it absorbs energy but it doesn't radiate it? Where does the energy go? Think about it.
It would be more accurate and less pejoritive if the missing matter was referred to simply as "hidden";
"Hidden" carries its own set of cultural baggage. It implies that there's nothing different about it, except that we haven't looked in the right place. In fact, we know enough about dark matter to say that it's physically unlike anything we've found on Earth. Moreover, we now know where it is.
hidden from we who do not yet have the eyes, technical or otherwise, to "see" it.
We've ruled out seeing it by the strong, weak, or electromagnetic means. That leaves only gravity (which we are using as best we can, indirectly) and some undiscovered, untheorized, unanticipated force, for which there is otherwise no theoretical or experimental motivation to expect.