TheOptimizationIdiot - 5:30 am on Apr 12, 2013 (gmt 0)
Okay, I'll answer directly then...
When you're writing a hueristic (which is what we call the algo and no one really complains about the distinction even though there is a definite difference) you have to "develop it" meaning it's not an algo or "right" from the start, but eventually you could end up with one.
What they have is a heuristic, and there's a subtle but big difference between an heuristic and and algorithm... A heuristic basically provides best guesses, where an algorithm provides an answer; one singular answer.
So the question, "Why is it too much to ask that Google provide relevant information rather than irrelevant information from 'trusted sources'?" Is actually very simple to answer... You have a "trusted source" as a "seed site" (best guess heuristically) or even linked closely from a "seed site" (best guess heuristically, initially) and visitor behavior in the results indicates an "adequate answer", so it remains.
When you're looking to keep, win, impress, or present visitors with an answer which is what they're looking for and visitor behavior "backs up" a major brand (best guess heuristically), then that's the result you give first (default to) for a query.
You're worried and wondering about "right v. wrong" or "accurate v. most accurate" or "relevant v. not as relevant" answers, but they're dealing with 1,000,000,000,000 pages as possible results and they can't "know everything", so when visitors' behavior backs up what they start with as "seeds" or "initially thought to be accurate" which is presented as a default (initially), they keep presenting it. It would be silly for them to do otherwise.
To get an idea of what I mean and an idea of the size of the numbers they deal with, please, try to review a single 100,000 (even 10,000) page website for information and relevancy to specific queries and try to decide which page should show for every related query for searches on the site, then remember they have 1,000,000,000,000+ pages to deal with. The algo (technically heuristic) just isn't developed enough to deal with and present the minutia you're asking for yet... I would guess in the future it will be, but it's not there yet.
I think what I'm trying to say is:
When you deal with the numbers they do and visitor behavior indicates "extremely trusted" is accepted by a majority over "extremely relevant", "extremely trusted" is what you show as results, because that's what the behavior (or interpreted behavior) of what most people are looking for is and that's what keeps them coming back to you instead of going somewhere else.
It doesn't really matter what we know or think is better on a granular level, what matters to Google is keeping visitors happy and coming back for more, so if that's trusted rather than relevant, it's way better for them to show (err or the side of) trusted.