Hello there,
I can explain, and you can see the explanation for your own eyes, right there on the "reputation explained tab"
We do not consider the chances of winnings in the final score. Different players from different countries might have different access to games with a different RTP - based on the casino's deal with the concrete game provider and the country itself. Aditiononaly, there is a constant mathematical advantage the casinos have over the player, and due to that it's called gambling - you can lose. The longer you play, the higher the chances you'll lose will get. So we focus on the probability you'll be treated fairly instead. Put it easily, once you manage to win, the casino will pay you your fairly gained winnings.
Do you consider every casino you lost in as a bad one? What about other features?