The story in the Torah is described as lashon harah br Chofetz Chaim but is it
According to the sources Miriam was concerned about Moshe being an abusive husband. She mentioned this in private to her brother without intent to degrade Moshe. What should she or could she do differently? The Torah does not say it was lashon harah but simplt indicates she mistakenly thought all prophets were the same
(1) (Devarim 24:9): "Remember what the Lrd your Gd did to Miriam on the way when you went out of Egypt." The Torah exhorted us hereby that we mention verbally, always, the great punishment [leprosy] that the Blessed Lrd brought upon the tzadeketh, Miriam the prophetess — who spoke only about her brother, whom she loved as her soul...she did not speak in denigration of him, but only compared him to other prophets. And she did not speak so to his face to shame him, and not in public, but only to her brother Aaron, privately. And he [Moses] was not offended by all this, but in spite of which all her good deeds did not avail her and she was punished with leprosy for this. How much more so will other people, the fools, who are prolix in speaking "great and awesome things" against their friends, be severely punished for this.
(NaN) (2) And he [the speaker of lashon hara] also transgresses (Vayikra 19:18): "And you shall love your neighbor as yourself," whereby we have been commanded to be as solicitous for our friend's money as we are for our own, and to be solicitous of his honor, and to speak in his praise, as we are solicitous for our own honor. And if one speaks or receives lashon hara and rechiluth against his friend, though it be true, it is apparent that he does not love him at all — how much more so is he in violation of "as yourself!"