When you join the largest “catch all” instance, then you browse “all”, then you get the good with the bad. large means large, all means all. the point of the Fediverse is that you can create your own feed, starting from scratch if you wish, but nobody ever said that would be trivially easy. Federation gives you the ability to see literally everything, if that’s what you choose, but you have to choose whether you want “everything” to be the default or “nothing” to be the default. If you want showing everything to be the default, you can join the hugest mega instance available (lemmy.world) that’s what you did.

If you’d rather opt-in to new communities instead of having to opt-out, start small. Go join a very small or heavily moderated or both instance, or start your own using a whitelist that only federates with communities you know are okay.

Also consider that you don’t have to click on shit you don’t want to see. You’re choosing to go to “all”, you’re choosing to click, to engage, to be angry. Nothing you say or shout or scream or rant about is going to stop this stuff from being out there in the world. I understand you don’t want to see it, neither do I. That’s why I have joined a smaller instance that has already rather strict rules and relatively strong moderation, and I have further tailored my communities based on that, and when that fails and I occasionally see something I don’t want to see, I downvote it or hide it or report it and move on with my life, because that happens, shitty things exist, I accept that is part of the reality I exist in and I don’t have to like everything I see and if I can’t do anything useful about it I’m not going to lose my mind about it.

I’m not trying to tell you you’re using lemmy wrong but… you’re using it wrong.