Rather, I am questioning the meaningfulness of even talking about whether the speed of light is different in other parts of the cosmos.
Everything that we say about the speed of light depends on earth-based standards. I am questioning whether those earth-based standards are extensible throughout the entire cosmos.
And everything we say about the world depends on the things we see not being actually a strange effect caused by the interaction of the cornea with the cascade of ejaculate spewing from frantically masturbating invisible imps all around us; but we don't worry about that because it's some silly nonsense I just made up.
I can't help but notice that you're making exactly the same argument as creation in the
Falsifying a young universe thread. The argument is not improved just because you write better.