Some diaspora are similar to mainland people. You can see this in all cultures. Yes, there's a likelihood that Greeks in the U.S. or Australia have additional values than mainland Greeks, but this doesn't mean that they've lost 100% all their original Greek culture and values.
Take for example. There are Poles born in Germany, that may have a dislike of Germans as equally as Poles born in Poland. Yet at the same time there could be Poles born in Poland who love Germans as equally as another group of Poles born in Germany.
Culture, religion, politics, language, and other institutions can still travel with you.
Exactly. Couldn't have said it better.