Daf Yomi - Beitza 30 - Demonstrations against Chilul Shabbos by Reb Jay

The Rema writes that the rule that mutav sheyihyu shogegin velo mazidin, we do not need to inform someone that he is committing a transgression if the person will not listen, only applies to a matter that is not explicit in the Torah. An example of this ruling is regarding women who eat on Erev Yom Kippur until nightfall should not be informed that one is required to be mosif michol al HaKodesh, to add on from the weekday to the Holy, if we are certain that they will not listen. This is despite the fact that there is a biblical commandment to add on to the sanctity of Yom Kippur. Regarding a prohibition that is explicit in the Torah, however, i.e. the prohibition against eating pig, even if we know for certain that the person will not listen, we still inform him of the prohibition involved. The reason for this ruling is because one is obligated to rebuke his friend. The Biur Halacha writes that the ruling of the Rema refers to people who sin occasionally. People who constantly sin and they sin lehachis, to anger HaShem, however, are not prepared to listen to rebuke and one is not required to rebuke such people, as they are no longer included in the category of amisecha, your people. For this reason, the Chazon Ish was not in favor of people who demonstrated against chillul Shabbos, as he held that one is not obligated to protest the actions of these sinners, and if anything, protesting would merely antagonize the sinners and make them more hateful of religious Jews (from Maaseh Ish).