Please don’t assume that just because you personally don’t seem to be able to correctly identify a male person’s sex that female people cannot. It is very highly likely that female colleagues have indeed understood (even without being told) that you male colleagues with transgender identities are male people. And quite likely that your male colleagues will have correctly identified their sex too.
I would be highly concerned if your male colleagues ‘turned away’ a male gender non conforming colleague. And why on earth would you think that in public toilets that male people who are gender non- conforming would be ‘turned away’? Has this happened? Or is this an assumption because you personally could not correctly identify your colleagues’ sex classes?
Just because you cannot correctly identify male people’s sex class, please do not assume this is the universal experience. You seem to have used this lack of ability to support a ‘it is nuanced’ argument. It really is not ‘nuanced’. At all.
Your colleagues are male people. If they choose to not use the male single sex provisions, that is their choice. However, the rights conventions are that publicly accessible single sex provisions are based on sex. Not ever on gender presentation.
There are several reasons for this. One is that male people are subject to blanket exclusion from female single sex provisions based on sex class and not on how they appear. This is the only possible safeguarding policy that provides robust safeguarding. There is no evidence at all that a male person at any gender identity will be considered the same risk level of harming a female person by accessing a female single sex space. I absolutely trust my lovely male friends not to harm any female person, however safeguarding policies keep them out of female single sex spaces.
Also, it is now very well evidenced that even with lowered testosterone, any male person going though any part of male puberty will have physical advantages that female people do not develop. Including an average grip strength that remains 150% of the average female grip strength. Plus the lowest quartile of male people’s strength have strength advantage higher than 90% of female people.
Plus, there are many female people who will feel distressed at having a male person in that space. And again, your own lack of ability to correctly identify a male person’s sex class should not be considered in any way universal. Numerous posters have pointed out the body cue differences. Others include even a noticable difference between the top of the lip and the base of the nose as a proportion to facial measurements. And the depth of the bow and shape of the top lip. The shape of the skull is another difference which has been studied well. It is so different that it is noted that the composition of the brains in male and female people are different to accommodate the difference in shape and volume.
You keep mentioning ‘nuance’ . However, robust safeguarding policies are not ‘nuanced’. They are very clear and, to use your terms, ‘simplistic’ and ‘black and white’. No special treatment for any sub group of male people. And no forcing female people to have to make an instant evaluation about whether a male person ‘passes’ or not, nor assess whether they might be someone who will harm them or not on a case by case evaluation
Safeguarding simply does not work that way. Despite the fact that you either think it does or wish that it does.
If a male person understands that his presence may cause a female person distress, why would he be entering that female single sex provision at all? And no female person can give consent on behalf of any other female person, or the entire female population. It simply doesn’t work that way. Rather, the bar for consent needs to be set at the level of the needs of the female people that say ‘I need this space to be female only, no exceptions apart from a child up to about 8 years old.’ That is the minimum standard for consent.