Fariĝi is an intransitive verb (as are all verbs with -iĝ-), so it doesn't take a direct object, so no suffix -n.
What part of speech is flegisto here?
And never mind, the answer is: predicate nominative, renaming the men.
En "Kurso de Esperanto 3.0" oni lernas malsanisto! gxi devas esti akceptata
This word appears to be a Googlewhackblatt, in that the only place in the entire Interweb where it can be found by Google, is in the above sentence :-) .
Glorious! Thanks for tracking that down. Yet another example that in the 21st century there's no shortage of information, but sometimes good advice is hard to come by.
Why not multaj da viroj?