I don’t really have a dog in this fight but with the way fedi works right now, a lot of us are using the blocklist to filter out content on all, to increase positive hits and reduce spammy stuff/content we don’t want to see until our subscribed communities take off.
I’m not sure public blocklists would be as useful as you think, at least until fedi takes off a bit more or gets new algorithms for sorting/suggesting. Particularly because it would, indeed, be highly invasive.