The thing is though, with traditional forums you get a LOT of controls for filtering out the kind of users who post such content. For instance, most forums won’t even let you post until you complete an interactive tutorial first (reading the rules and replying to a bot indicating you’ve understood them etc).
And then, you can have various levels of restrictions, eg, someone with less than 100 posts, or an account less than a month old may not be able to post any links or images etc. Also, you can have a trust system on some forums, where a mod can mark your account as trusted or verified, granting you further rights. You can even make it so that a manual moderator approval is required, before image posting rights are granted. In this instance, a mod would review your posting history and ensure that your posts genuinely contributed to the community and you’re unlikely to be a troll/karma farmer account etc.
So, short of accounts getting compromised/hacked, it’s very difficult to have this sort of stuff happen on a traditional forum.
I used to be a mod on a couple of popular forums back in the day, and I even ran my own community for a few years (using Invision Power Board), and never once have I had to deal with such content.
The fact is Lemmy is woefully inadequate in it’s current state to deal with such content, and there are definitely better options out there. My heart goes out to @Chris and the staff for having to deal with this stuff, and I really hope that this drives the Beehaw team to move away from Lemmy ASAP.
In the meantime, I reckon some drastic actions would need to be taken, such as disabling new user registrations and stopping all federation completely, until the new community is ready.
Bear necessities you say? All that a modern bear needs is a pic-a-nic basket and a trusty sidekick.