I think this is a very fine distinction that would have to be settled in court and could go either way. I can only say what I think it should do. And to be honest I think copyright is garbage, but for it be consistent I don't think that this difference should matter.
I think an important distinction for me with federation though is that it's not just a push, you have to subscribe, so it's a two way street. It would be similar to an RSS feed, and I'm not aware of that having any particular implications for copyright. There is certainly no explicit acknowledgement of terms baked into either protocol, so I think the only reasonable conclusion should be that it doesn't impact copyright either way. That remains unlicensed and subject to the normal rules, which presuppose that permission is not granted.