Eve is vouching for Mal. And when Mal1, Mal2, Mal3 etc are all vouched for by Eve, then they are all trivially linked.
The far bigger problem is "how do you vouch for a single entitiy". How do you prevent Eve having multiple unlinked accounts.
Spam bots would use stolen/purchased credentials and get shut down. State-level bots would be free.
The only thing you could do is build an identity from scratch, karma as you will, but then if it was actually valuable people would sell that (see rich people buying high-powered gaming accounts for the lolz etc)