Fight or Flight? Self-Segregation is the death of the Church's Gospel mission

The list of companies being boycotted by various Christians and/or conservatives has grown rather long: Walmart, Kroger, Walgreens, CSV, Disney, Nascar, Amazon, Google, basically the biggest and most popular corporations in America, all having done something regarding guns, homosexuality, or politics to put them on "the list".  No, I'm not going to enter into the boycott argument, and yes, a similar list exists among liberals listing different companies (or sometimes the same companies for different reasons).  What do we make of this, and how does it impact the Church and the Gospel?
We are currently trending, heavily, as a culture and a country toward greater degrees of self-segregation.  Not the old-school racial segregation enforced by zoning laws and bat wielding rednecks, but instead a version we are choosing to embrace based upon politics/morality/religion, which is showing itself both in the urban/rural divide and in the coastal/interior divide.  The Red areas are becoming deeper shades of Red, and the Blue areas are becoming more uniformly Blue.  People are moving within their communities to neighborhoods were people are more like them (it can mimic racial segregation in that people who look like us are more likely to think/act like us, but it has now transcended that as well), within their states to areas where people are more like them, and within the country to states where people are more like them.  We are more likely to live in an echo chamber, massively assisted by social media and cable news/talk radio, where the only voices we hear are ones that reinforce what we believe and demonize what "they" believe.  Some of our politicians are thriving in these chum-infested waters, some talking heads are getting rich off of it, but the American Republic is much worse off.  {FYI, gerrymandering is a symptom of this, making primaries the only race that matters}.  I won't tell you how to solve this problem on the political/national level, but I can intelligently (I hope) ponder what this is doing to the Church.
In 1 Corinthians 15:33, the Apostle Paul quotes the Greek poet Menander when he writes, "Do not be misled: 'Bad company corrupts good character.'"  In that particular context Paul is discussing the resurrection and those who disbelieve it, people we would call heretics or apostates.  He utilizes a Greek poet to remind the Christian minority in Corinth that they can be negatively influenced by those around them.  In his next letter to that church, Paul broadens the warning a bit in 2 Corinthians 6:14-18 when he writes, "14 Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness? 15 What harmony is there between Christ and Belial? Or what does a believer have in common with an unbeliever? 16 What agreement is there between the temple of God and idols? For we are the temple of the living God. As God has said: “I will live with them and walk among them, and I will be their God, and they will be my people.” 17 Therefore,“Come out from them and be separate, says the Lord.  Touch no unclean thing, and I will receive you.” 18 And, “I will be a Father to you, and you will be my sons and daughters, says the Lord Almighty.”  Twice then, Paul warns about becoming too entangled, "yoked together" with unbelievers (whether the Lost or those who have walked away from the Light, i.e. apostates).  At the same time, the Apostle Paul spent decades risking his life to take the Gospel, as an observant Jew, among the Gentiles to show them the light of Christ.  Certainly Paul did not withdraw from the world, enter a monastery, and seek to be free from the 'infection' of the pagan culture that he lived and worked within.  Paul was aware of the danger, yet it didn't stop him from seeking the Lost where they were.
What then is the answer?  Jesus also highly stressed the need for purity, even emphasizing that our thoughts count as well as our actions, and yet he ate with 'tax collectors and sinners' as recorded in Matthew 9:10-17 (and Mark 2:15-22, Luke 5:29-39) 10 While Jesus was having dinner at Matthew’s house, many tax collectors and sinners came and ate with him and his disciples. 11 When the Pharisees saw this, they asked his disciples, “Why does your teacher eat with tax collectors and sinners?”  12 On hearing this, Jesus said, “It is not the healthy who need a doctor, but the sick. 13 But go and learn what this means: ‘I desire mercy, not sacrifice.’ For I have not come to call the righteous, but sinners.”  Nobody has lived a pure life of comparison with Jesus Christ, and yet he was willing to be scorned by the Pharisees, the group who stood for strict adherence to the Law of Moses and the rejection of Greek culture, in order to minister to the outcasts of society.  In fact, Jesus reprimanded the Pharisees for focusing on ritualistic purity without having hearts of mercy.
This seems like a contradiction in the Scriptures, a gotcha moment for agnostics and atheists to laugh at our silly devotion to 'God's Word', but it isn't.  Instead, it is something extremely profound and often overlooked by Christians (and Judaism before us): purposeful tension.  That's right, the Scriptures contain opposed but complimentary ideas that are designed to be held in tension.  It was a college professor of mine, Dr. Ronald Mayers, who first introduced me to the idea of a Both/And rather than an Either/Or perspective in Scripture. {Both/And: A Balanced Apologetic by Ronald B. Mayers}  Not all issues, to be sure, but many of them contain a Both/And element.  For example: As Christians we are already saved, and yet we are not yet what we will be for we our sanctification is ongoing.  We are already in Christ, but not yet Christ-like.  Likewise, we believe in the sovereignty of God and the freedom of human beings to make real decisions, both God's will and human freedom.
Which brings us to the current situation in America and within the Church.  At the same time we are called to be pure, 1 Peter 1:16, " for it is written: 'Be holy, because I am holy.'" AND Matthew 5:13-16, "'You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled underfoot.
14 “You are the light of the world. A town built on a hill cannot be hidden. 15 Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. 16 In the same way, let your light shine before others, that they may see your good deeds and glorify your Father in heaven."  We must be 'in the world, but not of the world' (An attempt to summarize the teaching of Scripture on this issue), a delicate balance but one we must not shrink from finding.
This is our challenge as the Church in America in the 21st century.  We are interacting less and less with those who are non-Christians, and even those who are fellow Christians, but who disagree with us.  We are called to be salt and light, but within our own echo chamber, what good are they?  We are called to not be "yoked together" with unbelievers, but also to eat with "tax collectors and 'sinners'".  As much as we might want to retreat into our own world, to wall ourselves off from that which makes us uncomfortable and that with which we disagree, we cannot.  We must be pure, but not at the cost of disengaging from those who live in darkness. {As some are calling for us to do, see one popular version of the retreat strategy: The Benedict Option: A Strategy for Christians in a Post Christian World - by Rob Dreher}
Our mission is not to save ourselves, our mission is not to save our church, our mission is not even to save The Church, our mission, given to us by Jesus Christ, is to use the Truth of the Gospel, empowered by the Holy Spirit, to save the World.  Salt must stay salty in order to be effective, but salt left in the salt shaker doesn't help anyone.