This is not going to be a blogpost about “Why do people still use Reddit instead of everyone moving to Lemmy?”. I noticed that even with Mastodon users, who already understand and like the advantages of decentralized platforms, the usage of Lemmy is extremely small, and more people use Reddit. Most of them haven’t even heard of Lemmy. To be fair, the Reddit usage also seems to be fairly low.
Default blocks are difficult, one of the things the dev of the Tesseract frontend got absolutely roasted for a few months ago was for how aggressive the block list was and blocking Blähaj just reeks of transphobia. (The primary issue was his lack of disclosure of the existence of the block list.) There is no low controversy way of making a default block list beyond what we already do with most instances defederating a couple of the most egregious instances.
Tesseract didn’t disclose it, if you make the messaging clear then it can work. A button like “Block political communities” with a full list of what’s being blocked and a link to the page to edit your block list.