sick

Oh, there's absolutely no doubt in my mind that they all considered themselves to be Greeks. Where this subject is concerned, however, it's all in the details.

1) Magna Graecia was a term coined by Romans long after the 8th century B.C.E. colonizing movement of Euboan and Doric settlers who crossed over to S. Italy and Sicily.

2) There was no Magna Graecia by the time the events we're discussing occured (late 3rd century B.C.E.).

3) While Greeks throughout the world were connected by cultural bonds, there was no Greek "nation" for more than a few years in those ancient times.

Syracuse was a separate political entity from the city-states and kingdoms of Greece (the homeland), or mainland Italy. The concept of Greece (Hellas) as a nation, is raised only a few times in antiquity by orators and poets--generally whilst trying to muster up a sense of unity in the face (or wake) of invasion (see Pausanias after the Battle of Plataea, for example).

A Syracusan of his era would have been deeply suspicious of your subvertive tone. You'd sound like a pamphleteer trying to stir up public support for an invading Epirote on an imperialistic adventure, or something like that.