Maybe I'm missing something, but I don't see how this has anything to do with "cracking" the algorithm, or really with cracking anything.

YouTube openly admits to having a metric for scoring videos, which, of course they do. Then they accidentally, seemingly, leak the scores of videos. It turns out that content that is really successful on YouTube has a really high score. Meaning the score... works.

I suppose there's the question of whether the score is the cause or an effect of the success of these videos, though it's almost certainly a bit of both, since that's how virality and feedback loops work.