According to the explanation, "regular match" doesn't take into account the closeness of your ranks, but rather the similarity of one's playstyle. Rank is a measure of the amount of time that you've played; in direct matching its influence is negligible.
In other words, people who focus only on improving their kill count will largely be matched against other people like them. In short, kill count, death counts and paint points are the three criteria by which matchmaking is accurately assessed.
Initially, we wanted to make ranks vaguely map to the match-making criteria (?) but gradually began to feel that it just wasn't working. At last, we solved the mystery.
Of course it's not a perfect system, so once in a while players might notice and think "I've been ranked here?", but hopefully players will come to the realisation that they've been assuredly put into the same category as like-minded players (lol).
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this was kinda difficult to translate, not sure if I got all the nuances...
that seems really interesting. pretty smart way to go about matchmaking if it proves to be effective.