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It is simply incorrect to say if it can be slowed then it can be sped up. That has no scientific basis in reality. You can always slow something down by creating an obstacle for it which is what happens when light is slowed down. However, light has no mass hence why light can approach the speed of light. Other objects can't approach or exceed that speed because they have mass.
Also Brett confuses special and general relatively. In special relatively, nothing can travel faster than the speed of light. Special relativity is with respect to local laws of physics. In the case of a galaxy far away from us, it can be perceived as moving faster than the speed of light because it is far away and because space itself is expanding. The galaxy itself is not traveling faster than light but because the galaxy is far away and space itself is expanding, our perception is such that it appears to travel faster than light which is allowed under general relativity since that is a global effect with global meaning the medium through which something is traveling is creating the appearance of FTL travel.
This has zero implications with respect to light heading towards us as light heading towards us gets less and less far away and thus is a local effect and thus due to special relativity can't exceed the speed of light.
I'm sorry, but I had to chuckle at that......