Different people can interpret the same social phenomena in different ways and subjective experience can differ between individuals. That your experience differs from mine doesn't negate mine.
There are objectively far more hits when you search HN comments for "people" than "humans". So while I would not negate your experience, I would say that your assertion that "at least on HN, almost no one refers to "people" anymore". There are 5 million hits that would say otherwise, more than 3x as many for "humans".
I also don't recall seeing people use "humans" excessively, or in a way that sounded off to me.