So what we've learned here is that nobody reads, or is able to read. The criteria are CLEARLY defined.
All of this weeping, "I won a game, and I din't get many points",
'I'm bronze and a new player is bronze, too", "I've won trophies, but I'm only Gold". The formula is right there in the explanation. Recent games matter more. Playing in many leagues matters more. Beating a highly-ranked team matters more. Winning matchups matters more. It's a recipe of stats, not a single item. Winning a few games will not make you Diamond, in the top 1% of fantasy players, like me. I LOVE this feature, as well as the owner comparisons.
William Perkins commented
I thought Diamonds were the people who were Commissioners of private leagues that locked all of the other owners out?