Rot13, granted.

There is a connection between the two, but Quirrell strikes me as someone who has learned how to be Voldemort but whose terminal values remain on the light side.

Non sequitur. We have no evidence that Voldemort is necessarily "evil," only that he committed atrocities. It is possible that an extremely cynical, but otherwise rational David Monroe decided that the best way to save the world was to rule it, and the best way to rule it was to become a hero, and then went about the dirty business of becoming heroic enough to qualify for world domination.

In fact, I rather imagine this being likely. Quirrell as we know him does not seem like the sort of person to have fame, money, or even really personal happiness as terminal values; if nothing else, he seems like the type to take over the world just so he doesn't have to deal with complete morons anymore, and/or get off this planet.