kmoustakas
Scourge of Xaos
I don't think εξώνυμο and ενδώνυμο mean what you think they mean.And thats all well and good except you just said
As though it wasnt just an issue of exonym vs endonym
Greeks is essentially the name of a subrace of Hellenic people that happened to have colonies in Italy. They were the first contact the people who would later become the romans made with us. So they called us all 'greeks'. It's like calling all dwarves derro because you met the derro first and it's easier to say. When we tried to explain the difference to them they coined the phrase "That's all greek to me" (joke!) and at the time we didn't care because they were unimportant barbarians*. Then they took over the world and THEY didn't care what we told them. They told the world we are called greeks in latin and we are good roman citizents and that was it for a while. Well, we got renamed into byzantine citizents then mongol slaves then ottoman slaves but they also didn't care what we told them our name is. Ottomans actually kinda did, they used it on purpose as a derogative to describe us as uneducated shepherds which technically at the time was true. Being ottoman slaves was the opposite of fun hence we revolted a lot. We never revolted under the Romans - we kinda assimilated the byzantines actually - and we weren't dumb enough to revolt under the mongols!
Technically Greek is not even the name of a hellenic subrace, it's the name of ooold oold people before even the minoans or myceneans who were taken over and entirely assimilated by the Hellines. But the before-romans didn't care. Kind of how the english call ananas pineapple. "Γραικός" aka "Greek" is the name of a mythical person. He's the hero of the local Noah's myth. His people, the "greeks" were the ones who survived the cataclysm. Then King Hellinas conquered them and told them "you're all named Hellines now". It's also quite possible that it's an ancient word for 'old man' and "greeks" translates to 'old people' They are very similar! "Γραίος". Now obviously my history books are different than your history books and besides, history gets rewritten and overwritten all the time. When I was going to school we were taught about the descent of the dorians but that kinda turned out to not be entirely true. For now.
TL;DR we really AREN'T "greeks" but foreigners don't really care. Which makes total sense. Most hellines don't even know or care. The problems of having ~ 5000 years of ethnic history.
* Fun fact: the word barbarian was coined by the Hellines to describe foreigners. Foreign languages sounded like barbarbar (our equivalent of blah blah blah) compared to the musical tone of ancient hellenic.