It's been pointed out to RR several times now, that in my first post to him... the one that started him ranting... it was stipulated that light's speed is medium dependent... in the SAME sentence.<quoted text>
It's not wrong.
Incomplete, maybe, but not wrong.
Your statements, that the speed of light varies, are equally incomplete, so by your own admission they are also wrong.
Your statements that the speed of light varies, should read something like, depending on the medium, or when going from one medium to another.
When light is travelling in a single medium, its speed does not vary. It is only "c" in a vacuum, but its speed will be constant for each medium it travels in.
You can admit you were wrong now.
It's also worth mentioning that the post was me participating in a separate discussion... where RR was wrong about some things he read elsewhere. There was no question that he misunderstood what he read... so, rather than accept that he was wrong, he decided he'd attempt evasion.
It's how he rolls...
... into a wall.