I think a great many men view it through the the lens of saying no to something a male person wants is mean and infringing on liberties. The attitude rarely extends to women though, I expect we're just selfish when we want things.
I'll apologise in advance because this post may turn into a load of post modern bollocks. I think I'm on to something but I'm not sure I can explain it...
“The greatest trick the Devil ever pulled was convincing the world he didn't exist”
IMO the core and driver of gender ideology is not actually the false construction of Woman as a gender but the false construction of Male/Man.
Trans women are rejecting this image of what a Man is, but Trans Orthodoxy's construction of trans women as women allows this to happen without challenging the construction of Man itself but in fact reinforcing it, because it says "if that's not you then despite your male body you mustn't be a man, you must be a woman". Trans men identify as men yet are not forcing redefinition of Man in anything like the pervasiveness that trans women (or rather their allies) are forcing a redefinition of woman. The right wing/small c conservative mindset sees the debate as arguments between various groups of not-men.
In the middle, untouched like the eye of a hurricane, is the self image of men as the calm, neutral and logical objective observer. Only Woman is a thing in flux, the thing that has to be recategorised and redefined.
So all the fire and energy and anger and sense of wrongness generated by Men co-opting the right to "neutrally observe" (but in reality define) reality is being deflected away from challenging that image and towards women and non-conforming males.
But since it's the tension and disconnect between that incredibly limited conception of what a man is and the reality of how different male people really are that is powering the whole thing, I don't think it will stop until either we start looking at that blank hole in the middle, or society restructures and settles around ideas of gender that accommodate the real-word variety of males without challenging that constructed neutral Man. And losing female voices will be collateral damage.
Why am I going off on this tangent in a thread about Johnson and the Tories? Because Johnson epitomises that self image (delusion) of the white privileged male as the default, neutral view. It's the voice that wrote our history books and prides itself on being able to debate without getting emotionally involved.
So I can absolutely see that Boris would support self id because to do otherwise, to ask at what point a gender-non-confirming male stops being a man, requires turning analysis onto that blank shape Man and acknowledging that it's just as much a construct as the much-analysed Woman, and the Men who identify with that construction of Man just can't do that because it means destroying their own self-image.