You wouldn’t want instances to automatically store media posted from other servers, because that means that as a server admin you’ll have to deal with purging things like child porn from your server because some dickhead decided to cross post their trash to your community.
Wouldn’t you need to moderate the contents of the community anyway? Does it fundamentally change things whether the cross posting is done via posting from a different instance or by the poster just switching accounts? In either case the post is ending up in the community and you still need to moderate it. Having media stored in your home instance just makes things really awkward because now as a user I have to contend with both the server wide rules of my home instance and the rules of the community I’m posting in. I just worry we’re going to see things fracture into two nearly completely separate fediverses, there will be the NSFW adult fediverse, and then the SFW fediverse and you won’t be able to subscribe to content from one on the other.
You’re thinking about this purely from the standpoint of stopping spammers/bad actors, where as I’m trying to approach this from the standpoint of a well meaning user just trying to follow the rules. The current system does stop people from intentionally abusing the system, but it ironically can lead to people unintentionally abusing it. E.G. say I as a “normal” user with no knowledge at all of how the federation is actually implemented (not too far from the truth) decide to post into a community whose content violates the rules of my home instance (but not the instance the community is hosted out of). I would (incorrectly it seems) assume that as long as I was abiding by the rules of the community I’m posting in, that I’d have no problems, however doing so could see my account banned from my home instance.
In our theoretical example of a lemmy server run by PornHub, if I as a user of lemmy.ml want to post contents to a community hosted on PornHubs server I feel like I probably can’t as lemmy.ml, for reasons of moderation I assume, has a site wide rule against pornographic content. If I did reasonably post in good faith believing that the community rules took precedent I would likely end up in trouble with the admins of lemmy.ml. In order to avoid this situation I feel like I’d need to make an account on the PornHub instance and treat that as my main account. That feels backwards to me.
I can see where you’re coming from, but while the current solution makes things easy for the admins and moderators, I think it’s going to lead to a lot of confusion when/if lemmy instances that allow porn actually start showing up (I’m not aware of a single one yet). There’s also the question of text content that violates rules. If I post text content into a community in another instance that’s allowed by the rules of that community, but somehow violates the site wide rules of my home instance where does that end up? Does my home instance even know about it? It’s not stored locally I don’t believe. I presume the only way they’d become aware is if the admin/mod of the community being posted into complained.
