We as Christians need to get rid of the "them and us" mentality. Although I do enjoy hanging out with Christians I don't hesitate to reach out to someone who is not. How else am I going to share the good news of Christ if I avoid homosexuals, thieves, atheists etc. If I meet someone and I hit it off with them and I witness, as long as they don't disrespect me and my views, I don't mind continuing to be friends with them. I believe my relationship with God is strong and I don't believe being friends with people who are unsaved will change me, on the contrary them being friends with me will change them. It says in 1 Peter 2:12 “Live such good lives among the pagans that, though they accuse you of doing wrong, they may see your good deeds and glorify God on the day he visits us.” How can they see the blessings in our lives that God brings us for being faithful to Him if we avoid them? Now I'm not saying to constantly surround yourself with people who are unsaved because being with your brothers and sisters in Christ helps you grow in your walk with Him. But don't find yourself always pointing your finger at people who don't know Christ and turning your nose up at them, all that do is show Christians in a more negative light.
"While Jesus was having dinner at Matthew's house, many tax collectors and "sinners" came and ate with him and his disciples. When the Pharisees saw this, they asked his disciples, "Why does your teacher eat with tax collectors and 'sinners'?" On hearing this, Jesus said, "It is not the healthy who need a doctor, but the sick. But go and learn what this means: 'I desire mercy, not sacrifice.'For I have not come to call the righteous, but sinners." (Matthew 9:10-13)