Perhaps I should let this one die away quietly...but...
There are many problems with your arguments, and to counter them all separately would involve the exchange of another 50 or so posts. Like most over simplified arguments, if the fundamental underlying statement is proved false, then like a house of cards the rest falls to pieces, or at least demands the much more detailed analysis that you state is not required.
BW wrote:
And we know that, at very slow speed, there is little or no danger, and at very fast speeds, there is infinite danger.
This is simply not true -
At very slow speed there is significant danger especially to pedestrians and cyclists who view very slow moving traffic as being an open invitation to use the road as a pavement. This is demonstrated in official figures by a much higher accident rate for buses than other vehicle types, and most of these accidents happen at very low speed (<10mph)
http://www.safespeed.org.uk/pedrisk.html
At very high speeds, which in motor vehicle terms would be in excess of 150mph, we would expect that with the suggested "infinite danger" that drivers would perhaps get killed every few times they did it. Except that the German Autobahns and PC Mark Milton demonstrate that 150 mph+ doesn't result in inevitable death.
So high speed is not !infinite danger", and very low speed is certainly not "little or no danger". As many studies have confirmed, a major contribution towards accidents (bigger than excess speed even) is inattention. I don't know about you, but I mentally switch off when not being stimulated, and unreasonably low speed limits is a certain way of achieving this mental state.