They certainly don't filter out toxic people who make others leave companies because they poison the well.

The intent isn't to find good hires per se, but to whittle down the list of applicants to a manageable number in a way that doesn't invite discrimination lawsuits.

Same as why companies in the past used to reject anyone without a degree. But then everyone got a degree, leaving it to no longer be an effective filter, hence things like algorithm tests showing up to fill the void.

Once you've narrowed the list, then you can worry about figuring out who is "good" through giving the remaining individuals additional attention.