But that still makes a needless distinction, IMO, between Orthodox people in Greece and Russia (who are somehow not in the "diaspora"), and Orthodox people in other countries (who for ethnic and geographic reasons are regarded as being in the "diaspora"). My point is that ALL Christians are in the "diaspora" as long as the Kingdom of God has not yet come to earth - i.e., they are scattered/dispersed throughout the earth as strangers and aliens in this world...
That's a fine (and obvious) theological point, but it has very little to do with the actual usage of the word in its current manifestation, nor should it compel one to give up a perfectly useful and efficient means of expression.
In fact, in principle, your argument would disallow all distinction and description. How dare one say "Orthodox in the West" or "Orthodox in the eastern part of the U.S." or "Orthodox in the U.K." since that -- apparently! -- somehow implies that one believes that these Orthodox are not as much a part of the here-and-yet-not-here Kingdom of Christ as Orthodox in some other area.
We have to face reality. Every Orthodox Christian lives in a particular context. Some of those contexts are similar; others are not. And these contexts influence the way Orthodox Christians participate in, react to and experience the Church, which already is
the in-breaking eschatological community, i.e. a glorious foretaste of our true home, the Kingdom of Christ. Thus, even while the Church is one, the experiences and particular manifestations of that one Church are manifold; and this diversity can be broadly categorized and described. Like all verbal attempts at convenient generalization, such will not be perfect, but it will be meaningful.
Should you desire every time you are trying to make such a distinction to say: "Orthodox Christians who live in the old French neighborhoods of Bucuresti, as well as Orthodox Christians who live on the banks of the Volga, have these customs, whereas Orthodox Christians who live near UCSB along the coastline of California and Orthodox Christians who live near Houston, Texas do these things" -- by all means, do so!
But in its clumsiness of expression, such fails to grasp one of the essential realities that the distinction may be attempting to describe -- a distinction that has nothing to do with governments, established Churches, laws or citizenship. Rather, it has to do with culture
, i.e. day-to-day life, customs, how one makes one's entire life conform to the eschatological reality of one's Christian Faith.
Most Orthodox Christians in the diaspora face certain challenges to their Faith, especially in figuring out how to live in a practical way on a day-to-day basis as Orthodox Christians. Many have no access to a parish, since they live in areas where there is no Orthodox Church; others may have a parish with no priest; many may only be able to go to Church once a week; most are not able to take off time from work on major Orthodox holidays, since these are not only not recognized by the State, but also not valued by the culture; quite a few have very few Orthodox friends, little support in school, their workplace, even their home; sometimes, it is difficult to keep the fast, since most restaurants have few -- if any! -- vegan options and everyone is quite accustomed to cooking and eating meals with meat or cheese. In short, they have to figure out how to live as an Orthodox Christian (how to cook, eat, work, take vacation, pray, relate to their extended family and neighbors, budget for trips to parishes or monasteries), and such often poses very specific challenges and (sometimes) very few resources and easy answers.
While Orthodox lands (i.e. Orthodox cultures) are losing many of their particularly Orthodox characteristics, none of these things are wide-spread challenges for Orthodox Christians who live in, say, Greece or Romania. Rather, while there may be an emerging secular culture, there is also a large minority of people who are very active in the Church. Thus, whether they like it or not, Orthodox people in such places are surrounded by Churches and monasteries. They can interact with and learn from multiple clergy, experienced lay people, trained theologians and Orthodox families (Not too hard to find Orthodox playmates for young Yianni...just walk out your front door! No worries about what crazy ideas Yianni will learn in school, especially about religion, since Orthodox theology and history are required subjects for everyone!). People can -- and do! -- go to Church for Orthros or Vespers any day they like (I've been to a non-feast day Tuesday Vespers in Thessaloniki with 100 people...and that was just in some little Church I happened to be passing when the bells rang, as did the bells on two of the others Churches on that particular street). Businesses can and do close on Church holidays, people can stop by the Church on their afternoon walk and light a candle. Grandma shows you how to cook fasting meals that aren't unpalatable. In short, the cultural resources and customs can
support and deepen one's faith.
Try as we may, such things are often hard to come by in the diaspora. We have to carve them out of the rock of a competing society, whereas, in Orthodox lands, one has the example, guidance and approval of peer groups and a good chunk of one's neighbors. Not to mention the many holy sites, holy relics and nearby elders!