Absurd Variation of the Speed of Light in General Relativity

Banesh Hoffmann: Clocks go at the same rate in a gravitational field (there is no gravitational time dilation). The gravitational redshift "arises from what befalls light signals as they traverse space and time in the presence of gravitation":

http://books.google.com/books?id=JokgnS1JtmMC
"Relativity and Its Roots", Banesh Hoffmann: "In an accelerated sky laboratory, and therefore also in the corresponding earth laboratory, the frequence of arrival of light pulses is lower than the ticking rate of the upper clocks even though all the clocks go at the same rate. (...) As a result the experimenter at the ceiling of the sky laboratory will see with his own eyes that the floor clock is going at a slower rate than the ceiling clock - even though, as I have stressed, both are going at the same rate. (...) The gravitational red shift does not arise from changes in the intrinsic rates of clocks. It arises from what befalls light signals as they traverse space and time in the presence of gravitation." x

What befalls light signals as they traverse space and time in the presence of gravitation? They accelerate, as can be clearly seen at 3:34 in the following video, and this acceleration (predicted by Newton's emission theory of light) is the only cause for the frequency shift:

https://www.youtube.com/watch?v=1ENkP0h8nAg
3:34 : "But, if the box is accelerating, then the time between the light pulses at the bottom of the box will now be less than the time between the light pulses at the top of the box."

The authors of the video have no choice but to claim, in a confused and unconvincing manner, that the frequency shift is due to gravitational time dilation.

Pentcho Valev