@admin @p @john
Without access to the code I'm speculating, but from the docs I don't think "un-blockable messages" is how it shakes out.
It appears that Revolver has a single, distributed DB with content split across its nodes (strong whiffs of FreeNet!), but at the edges it exposes an ActivityPub-compat LitePub endpoint, to interop with rest of Fedi. It also promises content filtering of what each node propagates.
A Masto admin would treat that LitePub endpoint like any other instance.