No. Mastodon and twitter are short message services. Lemmy and reddit are content aggregators.
The moment you aggregate communities across instances you remove the ability to moderate them. Because maybe a hexbear mod wants to remove all mention of the Uyghur people, an ml mod wants to remove all mention of genocide against them, and a zip mod wants to remove all the comments about why genocide is good in a thread about god damned Bluey. Do they all get to delete everything across every instance? Do you start having different views of the same community depending on your home instance?
Instance A also cannot moderate the content of Instance B. Your argument is therefore invalid. The point of federation is that instances can agree on a common set of rules and values or not. In that case they defederate from each other. However, this doesn’t work in practice as communities are centralized. Obviously, most of us agree that lemmy.ml is a problem but we don’t federate just because they ‘own’ the instance.