Unbelievers aren't the only ones who like to quote this out of context...MANY believers do, as well. I find that they really only feel the need to do so when they know that what you're saying is right and it convicts them. For more on SCRIPTURAL judgment by Believers, read here!
"It should be noted that this passage has erroneously been used to suggest that believers should never evaluate or criticize anyone for anything. Our day hates absolutes, especially theological and moral absolutes, and such simplistic interpretation provides a convenient escape from confrontation. Members of modern society, including many professing Christians, tend to resist dogmatism and strong convictions about right and wrong. Many people prefer to speak of all-inclusive love, compromise, ecumenism, and unity. To the modern religious person those are the only "doctrines" worth defending, and they are the doctrines to which every conflicting doctrine must be sacrificed..."