Depends on the views of those doing the hiring.

Should you be allowed to not hire racists?

You are literally arguing against freedom of association. We get to choose with whom we do business! That is our right, as well as the status quo today.

I don’t hire smokers or ex cops, as I think they are unintelligent and assholes, respectively.

If it were legal I would never hire a practicing theist or anyone ex-military, as they are signs to me of low intelligence and poor moral character.

You have the right as a free person to discriminate against any non-protected group in service of your company and business.

Someone’s opinions are fair game for evaluation. Think Windows is better than Linux on servers? Keep moving. Think being a culture warrior in the US is a prudent move? Same deal.

All other things being equal, I prioritize people who have lived in multiple countries over people who haven’t. This necessarily means I am discriminating against those who have not.

There are a million attributes we can use to make hiring decisions. It’s not only legal, it’s prudent.

Here's the thing, authoritarians use abhorrent groups to justify authoritarian laws. It creates a power creep. Even well meaning rulers will push for more autocratic power with the justification that they can do more good with it. But unless you can place strong guarantees that no malicious ruler can come to power, you should evaluate powers as if they are the ones wielding it.

It's the entire concept of Turnkey Tyranny. A thing we are actively watching being exploited in America and across Europe. Because you can't prevent a malicious ruler from gaining power in a free society, but you can greatly limit their ability to do harm. But this can't be done with myopia.