She hasn't even said who that person is - so they can't even defend themselves. Additionally one person doesn't mean the whole family are horrible people.
Are the royals horrible people? Let's investigate!
* The wealth they horde is unimaginable. They have more money in the Queen's tiara collection than Musk and Bezos have combined.
* They continually petition against policies which would force them to make their wealth even slightly more transparent as this would be fully bad for PR when there are children starving in this country
* They continually protect sex abusers and pedophillic family members
* There may not be any family members who owned slaves still alive today. But they still have the receipts!
* Don't get me started on colonialism
* Let's not tar the whole family with the racist pedophile brush, I'm sure the various babies are currently innocent.
* They gave zero support to Princess Diana and quite frankly I'm not convinced by the opinion that they didn't have her killed.
This isn't just simply lumping in the existing royals with the atrocities committed by their ancestors, they continue to profit and benefit from the atrocities their ancestors committed with zero remorse or apology or disseminating of wealth back to the rightful owners, or be held to any consequence because they are the god given royal bloodline and it does not matter, they deserve all they have "worked for".
They are interlinked but separate matters, and to imply all slavers were racist is akin to implying all racists are slavers.