The short, definitely not legal advice version is that it only becomes a crime if you have actual knowledge that there is CP on your server, and you fail to block access to it and make the legally mandated report.

The law was written with ISPs hosting email and websites for paying customers in mind, but it applies equally well to anonymous user-generated content, federation, and other scenarios we may not have even imagined yet. Being an inattentive server admin is a valid legal defense, though actually having to use it in court would be stressful and expensive.

That can't be accurate otherwise it'd be incredibly easy to have maliciously taken down "the Fediverse" long ago. There might not be a direct Fedi distinction in the law and it might be too complex for the average district attorney to understand on the surface but that doesn't equate to "everyone is breaking the law" if something illegal shows up on a feed.