Citation needed. Cops visit black neighborhoods more, sure. But they do that because they commit vastly more crime. Which is the cause and which the effect?
It's also a lot more complicated than that. People throw out studies that blacks are more likely to be caught for drug crimes. But they are less likely to be caught for more serious crimes. Possibly because they trust police less and are less likely to volunteer as witnesses. E.g. https://www.wsj.com/articles/the-underpolicing-of-black-amer...