The Rambam (Yisodei Hatorah 5:10-11) writes that there are two ways to commit a chilul Hashem: either to sin, or to behave in a (otherwise non-sinful) manner that people view negatively. However he limits the latter to "a man who is a great Torah scholar and renowned for his piety":
וְיֵשׁ דְּבָרִים אֲחֵרִים שֶׁהֵן בִּכְלַל חִלּוּל הַשֵּׁם. וְהוּא שֶׁיַּעֲשֶׂה אוֹתָם אָדָם גָּדוֹל בַּתּוֹרָה וּמְפֻרְסָם בַּחֲסִידוּת דְּבָרִים שֶׁהַבְּרִיּוֹת מְרַנְּנִים אַחֲרָיו בִּשְׁבִילָם. וְאַף עַל פִּי שֶׁאֵינָן עֲבֵרוֹת הֲרֵי זֶה חִלֵּל אֶת הַשֵּׁם כְּגוֹן... אוֹ שֶׁדִּבּוּרוֹ עִם הַבְּרִיּוֹת אֵינוֹ בְּנַחַת וְאֵינוֹ מְקַבְּלָן בְּסֵבֶר פָּנִים יָפוֹת אֶלָּא בַּעַל קְטָטָה וְכַעַס. וְכַיּוֹצֵא בַּדְּבָרִים הָאֵלּוּ הַכּל לְפִי גָּדְלוֹ שֶׁל חָכָם צָרִיךְ שֶׁיְּדַקְדֵּק עַל עַצְמוֹ וְיַעֲשֶׂה לִפְנִים מִשּׁוּרַת הַדִּין
There are other things included in desecrating God's name: when a man who is a great Torah scholar and renowned for his piety will do things that will cause the public to complain about him, even though they are not transgressions, nevertheless he has desecrated God's name, for example...if his speech with his fellow men isn't polite, or if he does not receive them pleasantly, but is instead a man of anger and strife. In such matters, commensurate to the greatness of the scholar, he must take particular care and act better than the law requires.
Since most of us are not great scholars renowned for our piety (at least I speak for myself), it would seem that our bad (non-sinful) behavior cannot constitute a chilul Hashem.
Does anyone know of a halachic work that disagrees with the Rambam and justifies the widespread perception that a regular person's bad non-sinful behavior can indeed be a chilul Hashem?