Fox's firing of Diamond & Silk isn't the problem. Fox's hiring of them is.

https://edition.cnn.com/2020/04/28/politics/diamond-silk-fox-news-donald-trump/index.html

Remember that Fox News -- and Fox Nation -- are, at root, news services. They provide news -- often, yes, tinged (or more) with opinion. But news is at the heart of what Fox does.

That is not what Diamond and Silk do -- or ever have done. What they do is entertain -- and they make money off it, with a helping hand from the President. As The New York Times noted in a profile of the two women in 2018: "They also sell Trump merchandise on their website and have embarked on a speaking tour that offers fans the chance to see them live for $50 a ticket (or $150 if you would like to take a picture with them and eat hors d'oeuvres)."