I dont know the full scope of the ruling but the gist of it was, if im not mistaken, that an employer cant sack someone because they identify as a gender other than their natural born sex  You are mistaken.  The ruling was that you cannot fire a man for doing something if you wouldn’t fire a woman for doing the same thing and vice versa.  Gender identity only comes into it because a genetic male who identifies as a woman is going to do some things that genetic women also do (like wearing a dress) and if that’s not a firing offense for the female it can’t be a firing offense for the male.  The argument is fairly narrowly based on the text of the statute and not any constitutional principle - Congress could vote to change the wording tomorrow and the court decision would no longer apply.  Ruling is here: https://www.supremecourt.gov/opinions/19pdf/17-1618_hfci.pdf (The original statute also has specific exceptions for male and female restrooms, locker rooms, athletic competitions and the like.  So you can fire a man for going into the women’s restroom, and this ruling doesn’t change that).