If you remove names and ages from resumes, the number of women and POC making it to the interview stage goes up, where they reliably do well. But people are still often discriminated against at the resume stage because they went to an HBU.
And people doing the interviews still tend to hire people who look and sound like themselves, because it makes them feel comfortable.
If you have a room full of people who went to similar schools/Unis, have similar cultural influences, otherwise similar backgrounds, they tend to think of the same solutions. If you've got a variety of backgrounds, usually most easily achieved by hiring women and POC, you get a wider range of problem-solving approaches, which makes you more money. Sure, you may find a white male who grew up poor on the streets of Puerto Rico and made it to Harvard, but since you've hired him (and there's a vanishingly small number of people like that), how is someone else going to hire someone with a radically different background and through process?
The simplest way is to look for people who are different than us middle-class white guys, which makes us feel worried because it decreases the demand for us.