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.
No it's definitely important imo. It broadens your perspectives. I'm not saying that white dudes aren't going to have anything of value to say, or that people who aren't should always be taken seriously, but a diversity of viewpoints is I think a good idea. Someone who directly experiences racism, misogyny, or transphobia is fundamentally going to have a different understanding of things to someone who doesn't, and if you don't make an effort to listen to those people you cannot hope to get a complete perspective. Of course, this doesn't preclude you from being a liberal.