A weak analogy; a student in Florida will have Facebook friends from many places; not only his home-town, but fellow followers of Facebook interest group or games; we have no reason to suppose Eusebius included anybody who wasn't Christian. 

Nor do I treat this as fiction: What I  said was that Eusebius may understand those numbers as poorly as his calculation that the Nativity  
took place under Herod
in 3 BC.
He asserts both and they are incompatible...

But if it were fiction: One of the points of Crime and Punishment is the populousness of Saint Petersburg; many Russian novels, on the other hand, make a point of the restricted social circle of a country village. If we had no other evidence, we could guess at the size of Saint Petersburg and the sixe of an average village (and especially the nobles in a village{ and not  be faacros of hundreds and thousands off.  PMAnderson