I'm not from U.S but why would black people decrease property values? Isn't this really about poor people (that in the U.S are more likely to be black) decrease property values?

Here's an example of the same house in the same neighborhood being appraised much higher when the appraiser didn't know there was a black occupant:

https://www.ktvb.com/article/news/nation-world/jacksonville-...

Money quote: "... because in the Black community, it’s just common knowledge that you take your pictures down when you’re selling the house."