one important idea of Rav Nahman {of Uman and  Breslov}is that not everyone is fit to rebuke, o even though it is one of the 613 commandments to rebuke anyone who is not acting properly, still not everyone i able to give rebuke. For by rebuke that is not proper one can make things worse.  However  "מחאה" is different than rebuke. That is the need to object  in public to actions that are not right. Like in the incident of Kamza and Bar Kamza. One person was invited to a wedding feast by accident. There was a mixup of the wedding invitations. so an enemy of the family was invited to the wedding. When he was thrown out many of the religious scholars were there but did not object. Because of that incident the sages aid the second Temple was destroyed