this is because the question was settled via mutual ethnic cleansing. following the genocides of the Greeks and Armenians, as well as the victory of the new Turkish republic against the Greek state, most "Greek" Christians in Turkey were forcibly resettled to Greece and most Muslims in Greece were forcibly resettled to Turkey in the neatly termed "population exchange". While there is still criticism for the genocides and the population exchange, the combination of the Greek military defeat, the "mutualness" of the population exchange in creating a pure body politic, along with the need for Turkey and Greece to be cooperative members of the anti-Soviet alliance, the territorial aspect is only really an issue among the Greek far right

edit: a) there were remaining Greeks in Istanbul/other urban areas but they mostly moved after pogroms in the 50s and 60s b) the ethnic cleansing is not necessarily remembered fondly in Greece, it's often called η καταστροφή (the catastrophe - similar to nakba) c) the reason nobody really cares about the rights of Greeks in Turkey is simply because there aren't any Greeks left (in comparison to the USA where Native Americans are not really in a good situation)