Most of the statements you make are false in their connotations, but there's one statement you make (and attribute to "Bayesian Bob") that seems false no matter what way you look at it, and it's this one: "A statement, any statement, starts out with a 50% probability of being true" Even the rephrasing "in a vacuum we should believe it with 50% certainty" still seems simply wrong. Where in the world did you see that in Bayesian theory?

For saying that, I label you a Level-0 Rationalist. Unless someone's talking about binary digits of Pi, they should generally remove the concept of "50% probability" from their minds altogether.

A statement, any statement, starts out with a probability that's based on its complexity, NOT with a 50/50 probability. "Alice is a banker" is a simpler statement than "Alice is a feminist banker who plays the piano.". That's why the former must be assigned greater probability than the latter.