It wouldn't make sense to put the onus to block every bad instance onto every single user.
Consider the extreme use case, which is obviously CSAM. I rely on my instance admins to handle that for me. If I had to painstakingly block every instance that has poor moderation (or worse), I'd simply stop using Lemmy. The "all" feed would be utterly unusable.
Also, admins need control over what's in their own database, potentially for legal reasons.
This is where I’m currently at with “not technically nsfw but I don’t want people thinking I’m like that” trying to block anime communities centered around not-technically-nude pictures.
Yeah as an instance admin sorry not sorry I defederated most anime things like that. You want that? You host it. I don't need the feds knocking down my door.
The feds will knock down your door because a kid you headshotted in CoD called them. Anime is one of the more understandable reasons if we're being honest.
Honestly if the feds are going to even take the effort to move personnel to your house and knock your door, when it's quite unlikely the server is hosted physically at your house in the first place, you could take the opportunity to offer them cheap consulting on technology, international cultures (anime and stuff) and federation.
Heck, you can aim at their ego. "I tricked you, right guys? That means I'm pretty good."
An onus is a responsibility. A responsibility is power. It’s a simple fact that someone who chooses their own content source blocklists has more personal power than a person for whom someone else makes the selection.
And, it takes time and mental energy which we certainly don’t have to spare. It’s a very heavy onus that way