The whole 'we can't now sort out males and females, that genie's out of the bottle so we give up' thing just means that female people who won't or can't tolerate undressing or being vulnerable around male born people - and who have a need to protect children who are with them - will just be excluded from using those spaces. It will disproportionately affect vulnerable and minority groups of female people. It will, as the Target effect of an increase in sexual harassment and assault starts to bite, discourage more and more female people from using those spaces.
So either this is the beginning of the end of changing rooms full stop - although that doesn't solve the hospital wards, refuges, etc - or this is where everything moves to single use, wholly closed rooms and no communal spaces at all.
However this will still not solve the sexual and antisocial behaviour of some men (some men, please note the lack of generalisation here, this is evidenced stuff HQ) such as the individual on Twitter posting gleefully about wanking on the floor of cubicles and leaving semen stains on women's clothing that said individual then likes to return to the peg for women to unknowingly come into contact with. Or the issues of women supposed to use toilets where floor and toilet seat are covered in urine.
It comes back again and again to the need for the govt to clearly separate sex and gender. Fully supportive policy for gender identity to be met and supported in all situations, provision available in all circumstances, in addition to single sex spaces which can be used only by people of that biological sex. And support for all agencies and the general public to be fully aware of their right to designate and protect a space or service as single sex.