"Bias" measures deviance from a parameter. Without agreement on the population being measured and the parameter in question, the term--and quibbling over it--is meaningless. You are defining the population as something close to "people who possess the relevant skills," i.e. the pipeline. Others are using "people who possess the relevant skills but aren't in the pipeline" or "people who could possess the relevant skills if factors out of their control were accounted for". Others, still, disagree with how you're measuring "possess the relevant skills". This is all reasonable disagreement.