Dark matter is a fraud and many of its proponents know it is a fraud.
It's not a fraud. It's a scientific hypothesis. It may very well be wrong. That's why in science they do experiments. To find out.
The theory of "dark matter" wasn't dreamed up out of thin air, it is the most plausible explanation for objective data from measurements of the movement of stars within galaxies.
If there is no dark matter, something even weirder is going on, like that the gravitational constant is not a constant for very large structures. Such a finding would throw vast amounts of physics and cosmology into turmoil.