Arso, this is why i make it a point to always refer to the last Lubavitcher rebbe as such, even when it’s clear that I’m talking about him, because of how many people try to convince others that “the rebbe” is s term that implies the Lubavitcher rebbe.
In all chassidishe communities that I’ve seen, chasidim refer to their rebbe simply as “der rebbe” or “der rebbe zt”l,” so if a Lubavitcher says that, i have no issue with it, but when they make it out to be as though their rebbe was “THE rebbe” for the entire world… it’s chabad supremacism.
Cs, chas veshalom to say that the yidden didn’t mourn moshe rabbeinu! Rashi just means that the mourning was more intense because of what he did for their interpersonal relationships.