It seems to me a lot of companies are violating that policy, notably in tech in CA. How hasn't there been a major lawsuit? This has been going on for years and is getting progressively worse.
This is about first impressions without knowing the person. If one group has it substantially easier than another, you question that group that has it easier not harder.
If you hire based on physical traits it's only logical to assume that a person may have been hired based on criteria other than competence until you get to know the person. It's the unfortunate byproduct of these hiring practices.