Cavemen, ABC's bold foray into the single-camera, car-insurance- commercial-based half-hour comedy format, may not be premiering until October 2, but that doesn't mean we can't pass along this sneak preview. As you can plainly see, the critics who ambushed the freshman sitcom's TCA panel with knee-jerk observations about how this gently shaded race parable might rely too heavily on lazy stereotypes regarding one specific minority group were way out of line.