It’s not meant to be a stereotype applied to all men, just the a thing that some men do. It happens when a man assumes, perhaps subconsciously, that the woman he is speaking to is his intellectual inferior and would surely benefit from his opinion on whatever topic without any regard to her possible expertise on the topic, or even his own lack thereof. I’ve rarely witnessed it myself, but know women who have had to put up with it. Stereotypeing all men as “manslainers” would be rude, but mocking the men who actually behave that way is cool with me.
Yes, hallucination is the now standard term for this, but it’s a complete misnomer. A hallucination is when something that does not actually exist is perceived as if it were real. LLMs do not perceive, and therefor can’t hallucinate. I know, the word is stuck now and fighting against it is like trying to bail out the tide, but it really annoys me and I refuse to use it. The phenomenon would better be described as a confabulation.