"....during first Temple times, when peace reigned in the world, King Solomon personally traveled far and wide, and sent emissaries to foreign countries, in an effort to spread God's Word. Solomon sought to love all human beings, by virtue of their being God's creatures, hoping that this would bring about a union of hearts and enable him to have an impact on their spirituality. However, when you truly love someone and care for him, you become aware of his or her thoughts (Imrei Pinchas, Inyanim Shonim 72). Thus, gentile thoughts entered Solomon's mind. He did not realize that the thoughts of the foreign wives he had taken had poisoned his holy thinking. furthermore, the very struggle to lift someone out of the mud will inevitably dirty your own clothes. Thus, the very desire to rouse the buried holiness in the gentiles roused the gentile desire to bury the Jewish people in unholiness (Likuty Moharan I, 59:1; Resisey Lailah 57, p. 83d)." (Chanukah with Rebbe Nachman of Breslav)
If this was the case with the wisest of men in an era of world peace, how much more so now. Those Jews who are "going out to teach the goyim", "breaking down the walls of separation between Jew and gentile", forging bonds with xians, even spending time in xian churches and homes, under the guise of bringing them closer to God, are not only endangering their own souls, but all of Am Yisrael.
"So if you want to bring others close, you must be protected from negative influence. You must become aware of all your thoughts, learn how to assess your intentions, and become sensitive to any subtle changes that may occur within you. In short, you must judge yourself. Furthermore, not everyone can be brought close to God, and certainly not all the time. Judgement and discerning is required to know who can and when (Likutey Mohoran I, 59:5-6:Likutey Halakhot, Geirim 3:26), because even compassion for all of mankind is sometimes inappropriate (Likutey Moharan II, 7:1)." (Chanukah with Rebbe Nachman of Breslov)"
Many of the Jews involved in this "outreach to the world" are ba'alei tshuva and recent converts to Judaism from anglo countries. Many of these people are not only lacking in Torah knowledge but the Torah knowledge they do have, has been heavily influenced by western thought and values. These Jews also refuse to listen to rabbis who have advised them to stop what they are doing. Do they really believe they are immune to the gentile influence even though Shlomo HaMelech wasn't?
We can only influence the gentiles for the good instead of being influenced by them, when we live as a separate and holy nation. A nation of priests who serve and honor Hashem, not the goyim. By this we will be a shining example, a light unto the nations. We cannot reach this point without separation.