You're mixing up conditional and absolute probability. If it was down to three players (you, the person you seer'd and the person who you didn't seer), then it would be a true 50/50 from your perspective, and the blue seering tells you literally nothing since you can be confident both other players would flip blue. But there are more players than that, so it's the probability my blue flip is a wolf GIVEN that you can assume 2 out of 3 players were blue last night. Which is different still from the probability Oricorio's blue flip was a wolf given that you can assume 2 out of 5 players were blue N2.