A salmon and catfish are both fish. Do they taste the same? By your logic you can keep generalizing things until it's all under a single tag since it's all porn. There are differences in perspective which is why we have pre-established language for each. If they are the exact same we wouldn't clarify the difference. That is basic japanese, albeit a bit more adult. by there own existence the words contradict this notion. This is like trying to argue 2+2 = Carp.
The tag we have IS the sub genre, and the new tag system is already set the clarify it, so at this point all we can do is wait for that. It is entirely pointless to stir the shitpot.
As well, I'm sorry my dude but if your source is a random guy on Nhentai and you take that to heart you have other problems besides tag compliants. It's like people eating Tide pods cause they saw it on youtube. "Someone on the internet said if so it must be true" . Charles Darwin is rolling is his grave. Even if he was....questionable is his personal life.