If the speed of light in a vacuum is constant why cant it be used as an absolute reference frame?

Question

If the speed of light in a vacuum is constant why cant it be used as an absolute reference frame?

Answer 1

A reference frame is a coordinate system in which the position, motion, and other properties of tangible objects, or  the characteristics of intangible quantities or abstractions are measured and/or defined relative to that particular frame.

The speed of light in a vacuum is a measured quantity, not a coordinate system. You can see light, and measure it's speed, just as you can hear sound and measure it's speed, but you can't use either as a frame of reference. It would be like saying, let's use this particular photon, or maybe that one over there, as a universal reference frame.

I hope all that made sense. You have no idea how hard it was to come up with this. (Oh, man, my brain hurts.)