There’s a small, but extremely loud segment of the Mastodon userbase that seems to view presenting public posts in any manner that’s different from how a vanilla Mastodon server does as an invasion of their privacy. There have also been a few projects that raised reasonable concerns about privacy and moderation, but this page doesn’t seem to make a distinction.

It appears to contain misinformation about FediFirehose, which ran client side and just showed the output of a public relay.