Of course, but the reason is also understandable, no?
Imagine you run your own instance. Imagine after starting it up with sparkly eyes and going "OMG, people are joining my instance", one day a friend makes you aware "Hey you do realize you're hosting a social media community, yeah? Have you ever looked into the legal part of that? Like what content is or isn't okay, what users are allowed to post according to your country in correspondence to each other, how you'll handle DMCA and Netzdurchsuchungsgesetz takedowns, and who represents your site in court if you get sued?"... and then you realize fuck, you have no clue.
Now imagine then realizing you're the largest instance, and hence the target for anybody wanting to come after Lemmy as a system in any legal way.
It's fun to rant at the devs. However, unless you're the admin(s) of either lemmy.ml or beehaw, the only two instances large enough to potentially worry about this, you really don't have a good perspective on things. But imagine you were one of these instances:
- On the 21st of June, Lemmy as a whole reached 600k confirmed users.
- A lawyer firm writes you a letter, making you aware of linking to illegal content. This is fineable under some jurisdictions and with some content, Germany is one of these, where
lemmy.world is hosted. - The fine they can threaten you with depends on the reach of your link. Well, since Lemmy is federated, they cite 600k people exposed to that link for which you're responsible, the link is on your server after all (an effect of ActivityPub).
- It'll probably be something like a few hundred euros per exposure, but multiple that and they'll be threatening you with some crazy amount.
Now, of course, the number of exposures, the total sum and the idea that it's your link can all be attacked in court, to various degrees of ease.
However, you need lawyers for that. Specifically, you need money that makes those lawyers outlast the other side, as in these cases it's mostly about whether your money bin is deep enough so you can even see the case through to the end.
Imagine that, as a private person: Someone suddenly gives you the prospect of having to pay 5-6 digit legal fees. That's just the legal fees, this is all assuming you win, otherwise you're also looking at some 7-9 digit figure maybe. Would you keep federating with piracy instances? Or would you also go "Fuck it, this is my hobby project and IANAL, this isn't worth it"?
(edit)
Basically, from the perspective of the lemmy admin: If you want them to stay federated with piracy content, would you also be fine if they put your name (and you sign documents to this effect IRL) on the site as the legally responsible person for all content on it? Probably not, right? So saying they should keep content up is a bit weird. They're responsible for it, they are the only ones with any say in it. If you want your own say, make your own instance. But be aware that this also makes you legally responsible for anything, of course.