Anyone who defines it that way is missing the point, by making the mistake of defining science as just another belief system. The reason science works is because it's based on the evidence.
But that obviously does not apply to ""dark"" ""matter"". All there is to it, it's an effect that has been observed. Because it has the same effect we believe normal matter to be responsible for, "science" has labelled it "matter" though there is not one shred of evidence that it actually is some form of "matter" (the way we understand it).
The other problem is that it is factually invisible. Of course "invisible matter" is tough to sell to the public, so they decided to label it "dark" (which has led to some confusion in some Star Trek episodes where "dark matter" was used while in fact obscuring gas and other particles were involved).
Hence "dark matter" is as un-scientific as could be and reveals the limits of current science and our understanding of the cosmos and some celestial principles.
It's quite a cosmic joke that a catholic actor (reluctantly) provided the best answer thus far to the question what holds the galaxy together: The Force
I see your point, quote from Rob Knop: "The problem is that when actual real astronomers such as myself are confronted with plasma cosmology, we have a hard time doing anything other than shaking our heads sadly, because it's so amazingly wrong, so patently silly if you know anything, that it's difficult even to know how to begin saying that it's wrong."
Sorry, if someone ridicules the other guy before
dealing with the arguments, my life experience tells me something is wrong.
"As far as I can tell, plasma cosmology is motivated by people who just want to be different, or by people who have aesthetic or conceptual problems with things such as dark matter and cosmological distances."
Okay, I obviously do have an aesthetic and conceptual problem with dark matter for the aforementioned reasons. If that makes me a stupid person, I'm glad to be stupid rather than arrogant.
P.S. Apparently Professor Stephen Hawking, too, has problems with "dark matter". It's a subject he's not even touching with a 10 foot pole. I have several of his books and tried to put his comments on the issue together. It's a subject he gives a noticable wide berth which is so noticable it's actually remarkable!