"Sports car" isn't really a definition for anything... but I would say it includes the Tib. Why? The car is made to look and feel "sporty" - it's (in theory) fun to drive, looks hot, and some of them go like stink. I might not call a Tib a sports car in conversation, but from a manufacturers POV, that's the image they want to sell.
Same goes for any number of FWD cars - Si, Tib, Celica et al. are sports cars, yeah.