It must mean our perception is faster than the speed of the perceived object or light at all times otherwise the objects speed could not be measured.
For example trying to count the spokes in a movinf wagon wheel, on celluloid where the spokes can move backward sometimes.
But that could be a bad analogy.
So that is my idea: we can only perceive and measure phenomenon because were seeing them faster than their moving. If they were moving faster than our perception, then we would not even notice their existence, let alone measure them. So we can only measure c because our perception or radar is faster.
I hope my ideas are appreciated.