I mostly read (hard) sci-fi written by straight white dudes, so the tweet on the screenshot made me feel a bit defensive. In the replies and qrts people are patting themselves on the back for reading marginalized fantasy writers exclusively and this "consumption as activism" seems rad-libby to me, but maybe I'm wrong.
Diana Wynne Jones is a good fantasy writer. I like Trudi Canavan as well. Lots of good female fantasy writers out there.
That said, I also feel like this line of discourse (the tweet) is a classic example of "idpol without material analysis". It's just virtue signaling, and it doesn't help anyone. I don't think most people know or care about the author, and when they do, it's usually only after they've read the book and realized it's really good or really bad.