Two big instances were defederated by Beehaw recently because there were no sufficient tools to deal with problematic users. For detailed information have a look at the announcement.

Quote:

… [the] unfortunate reality we’ve also found is we just don’t have the tools or the time here to parse out all the good from all the bad. all we have is a nuke and some pretty rudimentary mod powers that don’t scale well. …

In case you want to see pre-moderated contet you can look at the mod log. I read a couple of pages some weeks ago. Besides a good amount of technical stuff like double posts, there was a lot of racist, trans-/homophobe content and general insults. What we see is the result of plenty of work done with insuffient tools. Keep in mind Lemmy is still 0.xx.