> Admitting the possibility of bias is very different than admitting bias in every single trending content decision.

They don't have to admit bias in every content decision. They have to admit systematic bias in content decisions in the aggregate, which does not necessarily imply bias in every content decision.

While it is technically, theoretically possible that their system is open to the introduction of these biases but does not actually exhibit those biases in the aggregate, it is astoundingly unlikely.