There was a reason for my question yesterday I only just got back to the thread - thank you Loops for answering.
Looking at the comments around this:
"Porn culture has such a stranglehold (sadly often quite literally) on dating behaviour and wider culture that one has to have an "excuse" - "I'm demisexual", "I'm a transman" - to gain "permission" to opt out of pornified behaviour."
And - yes - reading all about the definitions around demisexual aromantic and all of the rest of it - that many posters identified as being well within the range of normal behaviour / ways of feeling and therefore why do we need all these labels.
The whole thing strikes me as having a starting point in line with not just a pornified approach but the stereotypical masculine attitude to sex (which is of course the one reflected in most porn) - and of course this is what people were getting at.
And it's shown up by this response - because if these labels were about describing the variations and range of human sexual and romantic behaviours there would be a term for "bang up for it all the time". The fact that there is not, sets this as the norm against which the other behaviours are measures.
So again we have the "norm" being default male - in this case stereotypical masculine sexual behaviour - as catered to in most porn where of course all the men are up for it all the time with whoever crosses their path and catches their eye and of course in this story the women are too.
The fact that there is no term for this - and that sets it as the standard and norm - proves to me that these labels are as observed by so many a way for people - especially women - to excuse themselves from sex when they don't want sex or they don't want sex with whoever.
Oh sorry I'm grey sexual and aromantic is a good way of saying no iss off I don't want to fuck you and I'm not interested in getting to know you better either ta. It's a "polite" way for women to try to reject men in a new roundabout way and thus try to avoid the sodding awful behaviour you can get from men and boys you reject.
So it all makes sense really.
But to claim these identities as axes of oppression are ridiculous. Graysexual people, aromantic people, are simply not being wholesale refused access to services and sacked from their jobs. To put it in the same group as gay people, bisexual people when partnered with a same sex partner, these people have been and around the world still are being forcibly married, arrested, executed, attacked on the street, murdered.
Anyway this was the answer that pointed to "horny porn man" as being the current norm against which all other sexual behaviour is measures:
"Queen I don't think so? Desiring a lot of sex doesn't seem to be an orientation because it's expression of your attraction rather than what your attraction is. But I might be wrong".
There are words for not wanting it ever, wanting it with certain types of people, under certain conditions. Words for wanting sex sometimes but not others (surely most people) etc but no word for always up for it.