The Rambam explains one type of Chillul Hashem as follows (מיי' הל' יסודי התורה פ"ה הי"ד):
ויש דברים אחרים שהם בכלל חילול השם, והוא שיעשה אדם גדול בתורה ומפורסם בחסידות, דברים שהברייות מרננים אחריו בשבילן, ואף על פי שאינם עבירות--הרי זה מחלל את השם: כגון שלוקח ואינו נותן דמי הלקח לאלתר, והוא שיש לו, ונמצאו המוכרין תובעין אותו, והוא מקיפן; או שירבה בשחוק, או באכילה ושתייה אצל עמי הארץ וביניהן; או שאין דיבורו בנחת עם הברייות, ואינו מקבילן בסבר פנים יפות, אלא בעל קטטה וכעס; וכיוצא בדברים האלו. הכול לפי גודלו של חכם--צריך שידקדק על עצמו, ויעשה לפנים משורת הדין.
There are some other things included in Chillul Hashem [besides those involving overtly breaking mitzvos]. This is when a person who is learned in Torah and famous for his piety performs actions that cause others to denigrate him; despite the fact that they are not technically aveiros, this is Chillul Hashem. For example, if a person buys an item and does not pay immediately despite the fact that he has money on him, and the seller demands it from him and he takes the item on credit. Or, if he is excessively merry, or eats or drinks excessively among simpletons. Or, if he does not speak gently to others, and does not receive them kindly, but is often angry and argumentative. All of these sort of things are Chillul Hashem. A wise man must be scrupulous in his behavior and go beyond the letter of the law, according to his greatness.
When I was in yeshiva an incident occured where a student in the IDF refused to attend a military concert where women were singing and lost his position. Our shiur was discussing the halacha of the situation afterwards, and our Rebbe vehemtly disagreed with the suggestion that the student's action might have been a Chillul Hashem. This Rebbe said that when one is doing a mitzvah, it is not considered a Chillul Hashem if other people are offended by that mitzvah itself. What I took from this was that the Rambam means that in regards to non-mitzvah-related actions, one must act in a way that will not garner disapproval from others, but if one is doing an actual mitzvah, then if others disapprove it is their own fault that they don't appreciate the mitzvah, and therefore it is not considered Chillul Hashem. I don't know exactly what our Rebbe's source for this was, but I think the Chinuch agrees with him (see מצווה תכא: להניח תפלין על היד from "והמחמירים בקדושת המצוה" on, where he brings an opinion that it is a Chillul Hashem to wear tefillin when one's actions are not befitting, and argues on it).
Now here is my question: I was wondering whether this applies in the case where one is discussing or explaining Torah principles. There are certain halachos and hashkafic principles that are not "politically correct," and kiruv Rabbis and other Orthodox Jews who regularly interact with non-Orthodox Jews often avoid talking about them or whitewash them. (Examples: the issur to teach gentiles Torah, the laws of apikorsus, many gemaras discussing women, etc.) Now I understand that pragmatically it may be a bad idea to tell the non-Orthodox and gentiles about these details, since it might make it less likely that they will reach a higher level of avodas Hashem1. The question, though, is whether it is a Chillul Hashem to tell them about these things. Perhaps it is similar to the case of the incident I mentioned above, but this case is a little different since one is not actually performing a mitzvah. Would the Rambam say that one must "speak gently" and not reveal these things –slash– frame them in an overly positive way, or would he say that in the case of talking about Torah principles this law doesn't apply?
1(For example, the Rambam says on Avos 2:14 that דע מה להשיב לאפיקורס doesn't apply if the heretic is a Jew, since he may become more entrenched in his ways if you try to argue with him.)