It matters because tesseract was/is used by some large instances, so the tesseract dev was secretly censoring content from thousands of users without their knowledge and even without the knowledge of the instance admins. It's a pretty big deal because this means that a lot of people on Lemmy have been getting a highly censored view of the community without realizing it. A lot of those people, probably even most of them, came to Lemmy specifically to get away from that kind of thing. So its really shady, a huge breach of trust, and this single dev has been covertly influencing thousands of people's political exposure.