Yes, the main problem of the federated model is that you have house rules but global content.
The house rules make answering libellous statements on the global federated mastodon space that is copied everywhere very difficult.
The libellous Toots spread as in the song:
"Little by little, mildly,
in a low voice, hissing,
it goes flowing, it goes buzzing;
in people's ears
it enters deftly
and makes heads and brains
stun and blow.