I remember back in the late 1980's, when the muscle car hobby seemed to be exploding, how Muscle Car Review (then called Guide To Muscle Cars) kept doing "50 Fastest" lists. The lists kept changing as they found more and more original road tests (no web back then to look things up, they had to find old magazines), and then they began to add in then-current Vipers and Corvettes to the list, which always appeared at the top. Purists screamed that those weren't muscle cars, they were sports cars, so the magazine removed them from their lists, or came up with alternate lists.
It became painfully evident that many of the 1960's and 1970's cars on their lists were Camaros, Cudas, Challengers, and Mustangs, so people began to write in (remember those days when people wrote letters?) stating that ALL pony cars should be removed, as they weren't muscle cars!
For some reason, GTO guys like to separate out the Firebird when discussing fast Pontiacs, and they actually use the term "Pony Car" as a derogatory term, as in, "That's JUST a pony car, that's NOT a muscle car."
Over the past 15 years or so on the web, I've gotten into it with many GTO elitists who seem to think the Firebird is an inferior car in every way, shape, and form. However, I think I've calmed many of those guys down by providing facts, and even though it deflates their egos a bit, they finally acknowledge that the Firebird was indeed equal to, if not better than, the GTO in all aspects....except legroom.