The “rely on defederation as a solution to everything” implied here is the real issue, not the spam.
Discussion
Or the reliance on successful instances not growing out of control, without having a protocol level hard limit on size.
Right, the obvious outcome was obvious here.
Well, assuming these are actually the core assumptions and not a misinterpretation of them. E.g. maybe Mastodon went in a different direction than ActivityPub was designed for. I'm not familiar with the history and reasoning.
Yea no idea, I just know this outcome was obvious, so either they were okay with it or just didn’t know how to fix it and hoped.