Difficult question…Let’s see…maybe because these two countries are located in a continent called Europe? Could be that?
Then we can add up some tiny other details, such as Greece and Rome gave roots to the founding of the western civilization and that from Ancient Greece, the Roman Empire and the Italian Renaissance come the philosophy, legal system, literature, art, banking system (Florence) that all of us still use.
If you really want to judge Europe through a ranking system therefore, we can say that Greece and Italy are the “most European” countries among all other European countries.
Honestly, I’m more and more astonished by the ignorance of some people writing in here.