Because childhood nutrition, healthcare, schooling/community and other living conditions are huge causal factors towards a talent pool of people who are prepared to pass a software engineering interview? The original complaint here is all about 'seniority' being inherently unfair due to those societal conditions.

Trying to 'unbias' (meaning a calibrated, countervailing bias actually) at the other end of the funnel, where incidentally 80%+ are already super liberal, doesn't really get the same mileage.