I’m not a prude by any means…
… but they’re currently allowing communities dedicated to loli content. I just had to block a community that had titles like “after the rape” and containing animated material depicting minors.
I don’t know about others, but I don’t want that shit in any way coming across my feed when I try to look at All.
And clearly anyone who does want to browse other NSFW communities is free to make an account on those instances.
Easiest way to block NSFW content is in settings. Just untick, “Show NSFW content.” This will also block new NSFW instances as they crop up.