@Helen245
I agree with @Ann72 that your response to the review was very good. Is there any reason you did not leave a review for the guest? By the way, he appears now to have verified his account so maybe he at least learnt something, but there's nothing there to warn other hosts about his behaviour.
Airbnb rarely remove guest reviews, but I'm a bit surprised by this one. I should think that calling you a racist was indeed a violation of the content policy
https://www.airbnb.co.uk/help/article/2673/airbnbs-review-policy?_set_bev_on_new_domain=1633439893_M...
which include
- Profanity, name-calling, and assumptions about a person’s character or personality
In this case, I think that it's worth fighting for the review to be removed. Forget the rest of the review because Airbnb don't care when it's a "he said, she said" scenario. You should focus on him calling you a racist. That is not acceptable. If there was evidence of it, they would have (or should have) removed you for the platform.
If you do manage to get the review removed, make sure you ask Airbnb CS to remove the ratings too. They may tell you that's impossible, but it's not, because I have had a review + the ratings removed in the past. They can do it, they just say they can't.