But it appears to be a valid disproof, nonetheless. At least TK wasn't ranting in that one.
It is a valid disproof of The Knowledge's incorrect understanding of bendy light, if you want to look at it that way, yes. Incorrect things are often relatively easy to disprove.
How does "bendy light" behave when the sun is directly overhead? Does it still bend?
That's actually a very good question. If light bends outwards in all directions the. Their should be a dark spot directly underneath. I would also like to know the answer
Sorry, I haven't been in the upper fora much lately so I've only just seen this question. The amount of curvature on a ray of light changes with its orientation; it bends most when horizontal, and not at all when vertical.
When you are directly underneath the Sun, the light is going straight down towards you, so it does not bend at all. As you move further and further away from the Sun, the light is bending more and more to reach you. Finally, you reach a point where the light is curving to such an extent that it is horizontal when it reaches you, and so the Sun appears to be on the horizon -- this is what happens at sunrise and sunset.
When the Sun is even further away than that, there is no path that light can take from the Sun to you which does not go down through the Earth's surface and then curve back up again. Since light is blocked by the Earth's surface, you don't see the Sun at all. This is what happens at night.