Comment by kixiQu

In this case it's really about the burden of community moderation. It's a fairly impotent restriction, and yet it serves the social function of discouraging a certain sort from making Lemmy their home. Most Reddit alternatives become really scummy because they attract the people (not "the kind of people", the literal individuals) who get banned from Reddit for pushing anti-Semitism, racism, and misogyny past what Reddit allows. There are a lot of people who thus think "the whole point" of a Reddit-like that isn't Reddit is to be able to post the really awful stuff. The filter obviously doesn't work well to reliably block it -- but it does seem to work to drive off the folks who are looking for a cesspool.