Hoax is maybe not the appropriate word. We have observations that must be explained. This is what physics is about after all. Then, there are several ways to explain those observations and the dark matter hypothesis is one of them. The next step is to test this hypothesis (as well as any other) to see which will survive data.
So far, no conclusive statement can be made. Although no dark matter has been directly observed, the hypothesis cannot be ruled out. No matter one may want to 'accept' this hypothesis or not, only extra data (thus more observations) will be able to tell us whether it holds or not.
Okay now I can read :)
Hoax is maybe not the appropriate word. We have observations that must be explained. This is what physics is about after all. Then, there are several ways to explain those observations and the dark matter hypothesis is one of them. The next step is to test this hypothesis (as well as any other) to see which will survive data.
So far, no conclusive statement can be made. Although no dark matter has been directly observed, the hypothesis cannot be ruled out. No matter one may want to 'accept' this hypothesis or not, only extra data (thus more observations) will be able to tell us whether it holds or not.