I'd say my argument is pretty sound:
Enjoyment of video games is subjective. As a result, there will inevitably be variations between review scores among different critics. That's where Metacritic comes into play. It rounds up reviews from around the web to see what the overall average is. Eliminating low scores because they deviate from the average destroys the whole purpose of trying to find an average in the first place.
Yeah, but a crazy person doesn't know they're crazy; if they did, they wouldn't be crazy.