Why Did Moshe Sometimes Rebuke Overtly?

So the question must be asked, why in other places did Moshe need to rebuke them [B’nei Yisroel] blatantly even though he [Moshe] was such an ‘Ohev Yisroel’ [Lover of Jews]?

The Tzemach Tzedek continues; the response which Rabbi Moshe Alshich uses to answer this question - that Moshe Rabbeinu in his great wisdom started by testing their [B’nei Yisroel’s] ability to receive rebuke - is unsatisfactory.

Perhaps because this places Moshe in the dark as to his people and after spending forty years with them through the desert Moshe in the capacity of faithful shepherd would have known his people very well and whether they were susceptible to criticism especially when that criticism was coming from Moshe the ‘Lover of all Jews’.