It is common to hear Americans express fear and even outrage at the prospect of immigrants, especially non-Christians, causing cultural change within our society. This particular angst is very much a part of all the brouhaha about illegal immigration from Spanish speaking areas, but it is also a major issue in connection with all our political unrest and conflict.
It is noteworthy that those who identify as evangelical Christians are among the most ardent and vociferous in the opposition to immigration. These guardians of American culture see immigration as a diminishment of the longstanding influence which Christian Orthodoxy has exerted over all aspects of our society. For them, maintaining a national bias toward the Christian religion is a critical aspect of what it means to be American. Any actions or policies which suggest otherwise are anathema.
Ironically, these same evangelicals claim a sacred duty to reach and teach non-Christians all over the world, rescuing them from God's wrath. Their very label reflects a commandment by Jesus to go into the whole world preaching and converting. The vast distances which separate peoples of different languages and cultures has always made that commission difficult to execute.
With that in mind, having non-Christians come to a Christian society would seem the best possible evangelical environment. What could be more persuasive to potential converts than having them come under the influence of a society steeped in Christian tradition and example. The chances of hearing the Christian message and seeing its positive results are certainly greater here than in non-Christian areas.
To the extent that the Great Commission is actually important to them, one would expect evangelicals to relish the opportunity to interact directly with non-Christina outsiders, especially in what they believe is the most Christian of all nations. Rejecting contact with non-Christians, for any reason, is not going to aid in evangelism.
Of course, very few in the evangelical community are really thrilled with the responsibility to convert the world. They are too much consumed with the idea of condemnation and separation to ever get concerned about the spiritual welfare of the millions outside their comfortable, insular group. Try as they might, evangelical Christians will never figure out how to withdraw from the world and convert the world at the same time.
In reality what outsiders would learn from intimate contact with Orthodox Christianity is that it is not that different from what they knew back home. The story of the select few who are divinely blessed because of obedience and right practice is common to many religions. Additionally the idea that the religious few must oppose, suppress, and even eliminate outsiders is also nothing special. These non-Christian outsiders could probably change religious affiliations without giving up a thing.