Usage differences could be both geographical and time related. As far as derogatory use, "queer" and "homo" were used extensively when I was growing up in the 70s. In Junior High and High School, they were pretty much tossed around among the guys the same way as you would say "dummy" or "dufus". "*Not nice word for gay men*" was the more derogatory term, I guess when you really wanted to cut somebody down. I remember in High School , one guy used to think he was clever by calling people a "bundle of sticks" when in the classroom to avoid getting in trouble.
If "gay" was used at all, I recall it being what homosexual people wanted to be called (not that I recall any big gay movement stuff, at least in my neck of the woods, during that time). I never remember it being perceived as derogatory at the time, unlike its apparent place now. As a kid I certainly remember some of the older adults using "gay" in its original meaning, but very rarely. I also hear "that's so gay" thrown out a lot by younger people, even by inclusive progressives, and have no idea why it seems to be okay sometimes and not okay at other times.
