Because Starmer's workplace and social scene is dominated by the exalted idea of the Trans Child, and the current minority right to protect and promote at all costs, in this new age of intersectional grievances trumping good old fashioned class analysis, is transgender.
So it permeates his everyday working life, close contact with shadow cabinet colleagues with trans IDd children, and those who's raising d'être is the protection of this group.
And this is reflected in every layer of left leaning elite societal organisation.
EVERY left politician, journalist, doctor, charity CEO, social scientist, academic etc, has a trans IDd child (often more than one), or there is one or more than one in the extended family, or friends/work colleagues have one or more.
This is now "queering the pitch", in that the belief in the trans child is now the defacto mainstream belief, combination of herd mentality, purity spirals, intelligence being inversely proportional to common sense.
And these leftist elite parents are the epitome of combining extreme helicopter parenting with total Immersion into #BeKind #NoBullying #JustAccept, and the extreme social justice impulse for the trans child to be the first minority to never be downtrodden by society at large, no period of prejudice, no, the status will be exalted on day one, and brought into legal being.
No matter how many kids and women are trashed along the way.
Starmer doesn't even realise that this is a zero sum game, whereas we know whether he believes 100% 10% 1% 0.1%, or just one individual born a male can "become" a female is written into law, and female spaces perpetually up for grabs, the game is lost.