By default, all rights are reserved. Operating a Mastodon instance doesn’t grant anyone - Meta or mastodon.social - rights to redistribute the copyrighted content you post that is then federated.
I could legitimately DMCA most of the fediverse right now if I wanted to.
Aren't the protocols used for federation and clients different, i.e. could it be argued when one allows the protocols to be used for federation then one implicitly allows others to also federate?
I wonder if one could also DMCA ISPs providing proxy services, IRC or NNTP on the same terms and be successful.
I could legitimately DMCA most of the fediverse right now if I wanted to.