That's more a reflection of how bloated freestyle skiing is as far as a discipline is concerned. It should really be three distinct disciplines (freestyle skiing for moguls and aerials, park and pipe for half-pipe, big air and slopestyle and skicross).
I'm of the opinion that there should be a reorganization here, with freestyle skiing and snowboarding being eliminated as disciplines and alpine snowboarding, "classical freestyle", park & pipe and cross being the new disciplines (which is how the FIS really seems to think about and organize them anyway)