I kind of like riding the Little Miami Trail, because it's flat, and you can do a little people watching. Most other "serious" cyclists do avoid it thought, although I doubt many of them are exceeding the trail's 20mph speed limit.
Still, I've never felt like Cincinnati has been that bad for cyclists. The Cincinnati Cycle Club is one of the largest and oldest in the country, so there's no shortage of cyclists here to educate the car drivers. As with anywhere else, it's all about where you are, and if you happen to be in the territory of some jerk. I've ridden several times with the club out of Loveland into the back roads of Clermont and Warren Counties, and I've never seen any problems as the long line of us are climbing the busy Rt. 48 at 10mph while the speed limit is 55.
There is this one place where some redneck in a tan pickup truck lives, and whenever he sees cyclists, he floors the gas and pumps out as much black smoke as possible. I've been gassed by this person 3 times, and next time I'm going to get his plate number, because at the very least that's harassment.
I ride in the city a lot too, since that's where I live, and only once have I ever heard someone shout "get on the sidewalk," and it was some teenager in his tricked out Honda Civic down on Eastern Avenue in a not-so-great neighborhood. I've actually found that the worse the neighborhood (to a point), the more the people tend to just leave you alone. Even riding downtown by the Reds and Bengals stadiums has never been a problem, and I've been down there several times as people are coming to baseball games. So overall I think (hope) you've just been unlucky to run into a disproportionate number of jerks.