Yeah sure... However, I know of many true males who have a skull shaped more like the female 'example' above and vise versa, and as you pointed out the same applies with other areas of the body bone structure, which is why I find many (but not all by any means) of these example diagram somewhat misleading.

It's only misleading if taken for absolute.
There are no absolutes.
Even when discussing God, each of us has our own interpretation.
Belief and faith, yes, but describe God for example.
Discern the difference between an XY and an XX never was that important.
However, when your daughter is going into a bathroom and a large "woman" follows her, it can help to see differences.
And if your female friend is beaten to a pulp in a boxing match, which is unjustly UNMATCHED, then differences perhaps, shouldn't be allowed?
We didn't need guidelines for determining XX and XY in the past.
But now gender clinics have grown - almost astronomically in the US.
While surgery and medication might be a solution for some gender dysphoria, whenever something becomes big business, there must be questions asked.
So far, people are trying to find answers. Looking at the skeleton is not a bad answer.
DNA testing, another answer.
No matter what their sex letters are, people don't wish to see anyone hurt.