Do you see any problem in using the term you are trying to define in your definition of that term?
The person who asked the question states that he listened to the talk and did not hear any definition of racism. This is why he asked the question. If you're really curious you can listen to the whole talk (2). Not that I would recommend listening to the whole thing.
1. https://www.nytimes.com/2023/09/25/opinion/columnists/kendi-...