But, why were these posts rated so high...?

I seem to be saying this quite often lately, but reputations are aggregate values based on several factors: technical content, the presence or absence of siblings, presentation, author reputation, humor, misunderstandings, or just the desire to use up a vote. They're an imperfect, rough metric for gauging the relative utility of any given post in relation to its siblings, measured on too many axes to be useful.

In short: the system works pretty well. Everyone has a slightly different view of things. I don't know of any editor or god who cares enough about the occasional apparent inconsistency to write a better system. Anyone will always be able to point out cases where it falls down. I'll respond with the metric boatload of cases where it works as an 80% (or better solution).

What I'm trying to say is, yeah, it's not perfect. It's run by humans, after all. It's quick, though, it's here, and it covers most of the situations pretty well. I see no need to worry that one node is more "deserving" than another.

XP doesn't matter. Reputation matters only a little.