@3ammo The problem here is if you pretend we are newtonian people (which we are not since the world is relative and not newtonian) any attempt you make to measure the speed of light accurately will give contradicting and failed results, in part because you assume there is no problem synchronizing clocks when in reality there is.

If i just assume a newtonian world, sync up two clocks at rest then transport the receiving clock to a distance location, measure the speed of light, then bring the clock back and compare I will get one measure for speed of light. If i do the same experiment but this time the transmitting clock is the one physically moved I get an entierly different measurement for the speed of light. Since we are pretending the world is newtonian it essentially shows us little more than "it is impossible to measure the speed of light (using newtonian physics), you will get different values when irrelevant aspects of the experiment change!".

In short because relativity is more true than newtonian physics it is only using relativity you can measure speed of light at all (albeit it 2-way speed of light), and newtonian physics makes it impossible to accurately measure the speed of light at all.