The answer is really simple: light has a defect which means it slows up the farther it goes, therefore making far off things appear moving away from us faster. There is no dark matter: the dark matter is between their ears.
I watched a video the other day about how light speed cannot be measured without the use of mirrors. To measure it, it has to be shown at a mirror and then divide in half. The problem is the light speed to the mirror may be faster then the light reflected back to the measuring device. It was a fascinating video.