Didn't say they were and certainly there is bias.

Problem is, is that bias because of gender, because of race, or is there not an extrinsic bias on the part of the teacher, it's just that the aforementioned things disproportionately affect minorites and maybe boys more on a systemic level? Is the bias a direct result of the teacher "hating" boys or is it because the overall society has led to conditions where boys are failing to thrive?

It's easy to point fingers. It's harder to solve problems.