Does no one take Einstein seriously? All motion is relative. It all depends on your frame of reference, and no frame of reference is privileged.
Except perhaps for the microwave background radiation, which some cosmologists view as a universal reference frame for detecting absolute, as opposed to relative, motion.
For example,, the motion of our Milky Way galaxy is seen within the microwave background radiation map as blue-shifted on one side, red-shifted on the other. This is usually subtracted out when presenting the map.