This is a recognition in our sources that not all sins...or sinners, are created equal. Besides the different punishments prescribed in the Torah for different offences showing what is of greater or lesser severity of a particular action, the rabbis recognized other gradations. First, there is a huge difference between committing a sin because of passion or weakness, and one doing so as a show of spite or disrespect. Second, one who worships idols, or has converted out of the Faith, although remaining technically a Jew, is not to be regarded as such by the community. (A significant minority of opinions say that he is, in fact, no longer Jewish. This is not the accepted view.) There is a Talmudic ruling that willful Sabbath desecration is a form of idolatry, as Shabbat is a testimony that we believe that G-d created Heaven and Earth. Historically, a Jew who did not keep Shabbat, was, in essence, writing himself out of the Jewish people. When Shabbat desecration became common, with the rise of Reform in the Eighteenth Century, many were left in a quandary as to how to relate to our brothers and sisters who were misled into neglect of this most central observance. There were, and are, rabbis and communities that turn these people away, in the hopes of maintaining the pristine observance of Judaism. Most, however, were far more lenient. The Shulhan Aruch had already ruled that one who transgresses only privately, has not lost his status of credibility. Many pointed to a Talmudic dictum that one who refrains from violating Shabbat in front of a sage (showing that he is embarrassed), is still considered "kosher". Rabbi David Tzvi Hoffman (Melkamed L'hoi'l) went even further, opining that since Shabbat is not observed by so many Jews, most do not consider it as being such a severe transgression, thus rendering their willful transgression as accidental. Although this approach was rejected by Chofetz Chaim in Mishnah Berurah, it was accepted by Chazon Ish. In fact, Chazon Ish actually gave non Sabbath observers the honor of being called to the Torah. Many are lenient based on the concept of "Tinok Shenishbah" (a baby captured by Gentiles, who grew up without Torah knowledge), extending that concept to include one who was brought up without a solid Jewish education. However, as I pointed out in a previous series, that entire concept is based on a censor's correction in RAMBAM. Rabbi Moshe Feinstein was lenient to count non Sabbath observers in a minyan for the saying of Kaddish, but not for public prayer. Mahari Assad (19th century) wrote that Jews who have strayed should be encouraged to return, and in no way should be made to feel rejected. In my experience, most Israeli rabbis do not allow a non-Sabbath observer to be counted in a minyan, whereas most American rabbis do. My own policy is based on a teaching of Rav Ovadia Yosef, that a non observant Jew who comes to synagogue, and recites the blessing "Mekaddesh HaShabbat" (in Kiddush and in the Shabbat Amidah prayer), is not to be seen as one who rejects the Shabbat, and, although transgressing, is to be seen as a full part of the community.