Like theists' various gods, Dark Matter can't be seen (which is why it's dark), can't be detected directly, which means it doesn't appear to do anything, and can't be heard, not even in the broader sense of giving off any radiant energy (which again is why it's dark).
So, with typical hypocrisy and doublethink, theists often accuse science of using faith when it comes to Dark Matter as though for others faith fatally undermines an idea, but not for them, obviously. For them, faith saves their idea from dismissal through lack of evidence.
But of course, the reason for Dark Matter being suspected is because we can see the effects something is exerting on the surrounding matter in that something is providing the gravity which prevents rotating galaxies from flying apart under their own inertia.
In other words, Dark Matter is a scientific hypothesis to explain a natural phenomenon. Nothing more and nothing less. If and when a better hypothesis is produced, the idea of Dark Matter will be abandoned. If, on the other hand, evidence is found to confirm it, Dark Matter will be incorporated into the scientific theory of matter. Either way the sum total of human knowledge will increase and science will move a little closer to the truth.
Strangely, theists can never point to any unexplained real phenomenon which needs a god to explain it. Unlike Dark Matter, no scientific explanation for any phenomenon has ever been shown to require a god in it. In fact, the desperate attempts by theists to insert their god in any scientific explanation has always proved to be unfounded and so should have been pared away with Ockham's Razor as an unwarranted multiplication of entities and an unnecessary complication which always adds more complexity than it explains.
The difference between science and theology is that science starts with the phenomenon and thinks up ways to explain it; theology thinks up the explanation (invariably their god) and then either invents phenomena to justify it or thinks up reason to explain why there aren't any. In other words, science is honest and true; religion is neither.
Abandoning gods will do nothing to detract from the sum total of human knowledge and will actually move us closer to the truth by discarding an old and useless hypothesis which explains nothing at all. Our knowledge increases when we stop being wrong because we now know that the old idea was wrong.