Good question and my answer is strictly an opinion, So please correct me if I am wrong anybody.
When real Red Dragons came to this country from SE asia maybe 10 years ago or so, They were absolutely gorgeous fish. Vibrant red in color that wouldnt fade away, And I believe they came from Thailand. They were almost half red nad half white, and It was known as the perfected ZZ. And I beleive either Malaysia or Indonesia had a different idea of what a ZZ should look like and these came out more pearly and they may or may not contain gold monkey genes.
Now that brings me to the point of ZZ Red dragon today. I see these "so-called" Red dragons that look like they were crapped out by Trimac and Blood parrot, and I cannot justify calling it a Red Dragon. My Red Dragon (Sangria) was shipped to me from thailand and looks nothing like some of these abominations people are calling Red Dragons. Personally I feel that Red Dragon is a breed standard, Not a catch-all for slightly red ZZ's. Its mostly just for marketing anyway.
This is simply my opinion, Beleive it if you want too, If not thats cool too. Names are choas anymore with all the cross breeding and hundreds of different breeders. BUY THE FISH, NOT THE NAME.