That's not what bias means.

What bias means is that if there are two equally qualified candidates (as in almost exactly, so that it's a coin toss between them), then one from a certain background is consistently chosen.

If more applicants are available that happen to be from a certain ethnic group, and tend to be better qualified, then that's what the organization has to work with.

That is a societal problem; you can't just dump it onto the shoulders of an organization and require hiring quotas: "please fix the decades-long problem which brought these people to your door, with the qualifications they have, in the proportions you see".