Yeah, I agree. I think the important thing is "was the local content scrubbed?" Because at least if that was done, the place of origin no longer has it.
Federated deletes will always be imperfect, but I'd rather have them than not have them.
What might actually be interesting would be if someone could figure out this type of content negotiation: deletes get federated, some servers miss it. Maybe there's a way to get servers to check the cache and, if a corresponding origin value is no longer there, dump it?