I didn't even mention race, but commented on suspicious kids wearing hoodies in the summer, at night. I was called a "racist" for pigeonholing people who dress like that. I was even warned by a mod. I cancelled my account shortly after.
My NextDoor generally consists of the following:
1. Every hard luck story in the book, with people asking for money or other support.
2. Selling stuff or soliciting business, i.e., someone bakes and sells cakes and pies.
3. Asking for service recommendations for everything - car and home repair, handymen, etc.
4. Lost pets.
5. Complaining about local politicians and city/county issues.
6. Suspicious person notifications, usually with Ring camera video.
7. Asking about police activity seen in the area, i.e., why are all these police cars at XYZ location?
8. Coyote and snake sightings.
9. Graduation, birthday and other personal announcements.