I think it is.
From a tory perspective, law and order is an easier sell than care, I understand that, but also the 'traditional' view of nurses is that they are wives of 'real' breadwinners, and less than, and support staff to people doing the 'real' medicine.. Male doctors and this the root of Conservative thinking if whether nurses and teachers should be paid properly.
Similarly there is a 'typing pool' view of female university and council Admin and managerial staff that is similar.
The nurse = pin money job is I am sure far more embedded into old tory thinking than we would like to admit.
Feeding into this of course is if they raise the pay for nurses and teachers, a. Crony privatisation businesses won't be able to make so much profit b. Crony privatisation businesses won't be as easily able to offer a premium to cherry pick expertise from the NHS, so leaving the training burden on the state, but the profit gain disproportionately with the private companies.
But the reason doesn't matter, it's a gender biased pay rise within the sector, so a good basis for legal pressure imo