From what we could read here I do have an idea why stack overflow wanted to get rid of her. There is a whole encyclopedia of companies which have had bad experiences with the code of conduct people (creators or "enforcers" of the CoC, that is). Theoretically a code of conduct is a very useful thing, but more often than not people abuse the CoC to make internal politics. Ironically it's mostly companies that try to embrace equality and inclusiveness who have those problems, like it or not.
So while in "real life" I am a big supporter of LGBTX ideals, when it comes to software one should become very nervous when you hear people talking about their pronouns because they are usually trouble makers of the worst kind. People that are totally sensible and real great if you talk to them one-on-one can become real nasty when it comes to "armchair witch hunting" of alleged CoC breakers.
And this is really really sad because they are already marginalized and I support equal rights with all my heart. But two wrongs don't make a right and when people are trouble makers you don't want them in your community (or company), no matter how noble their ideals might be.
Personally I think we should _convince_ people to be open-minded and not enforcing it. Fighting for peace is like screwing for virginity.