General realtivity generalises special relativity and it is the relative movements in trying to make a reference frame that is causing Bill S problems.

Never forget that GR embodies SR it is important and just saying GR says so doesn't help anyone you need to move back into Special Relativity to see how there is a cosmic reference frame you can use.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.