Just to indulge in technicalities:
Regarding point #1, he’s probably correct, since neither him nor us know who and what. And as far as the girl who does, well she KNOWS not to believe nor trust someone who cannot possibly know anything. The Heading of this thread clearly states “Guys Please Explain This Behavior and because I gave a possible explanation, I am being vilified by the posters. Is it right?
Point #2 he’s probably also right, technically. He’s saying HE cannot be accused of motzi shem ra if it’s not certain there’s a falsehood. (no, of course he is NOT PERMITTED, but he cannot be ACCUSED of motzi shem ra.) If your standards for motzi shem ra are that you have to know 100% that what is being told is true. Then how are you allowed to ask Shidduch reference questions such as is the boy bipolar. As the only one who would know that is beside the patient and perhaps his guardian is is a medical professional who will lose their license to practice if they reveal any medical information to anyone else. If you asked a neighbor if the boy has mental issues by your standards you would be guilty of motzi shem ra.
Point #3 is wrong, as you wrote, as stated openly in the Chofetz Chaim. While technically you could be guilty of motzi shem ra even if you had no intent, you can not be punished in this world for a corporal or capital offense as you need to be warned to show clear intent. Since most of the prohibitions are negative commandment which are punishable offensives only if intent is shown.
If however you use my standards which is, if it is true it is Loshon Horah and if it’s false it’s Motzi Hhem Ra then intent maybe a factor. As R” Silber ZTL states in Oz Nidbaro vol 14 question 60, in a case of Loshon Horah where there is a Toeeles (reason) for Loshon Horah and would be permitted , if the intent is to embarrass or make fun of the victim them it is not permitted.