Indeed. The way I look at it, people are free to call me and say to me whatever they like. It's up to me if and how I respond. Some people say I ignore them but they soon learn. Or go away.
Sometimes it's not easy to learn new pronouns.
I'm fully with transgender issues however for 2 years I had a drummer called Aaron and one day we all got a message saying from that day she will be known as Aimee.
It was an absolute shock because Aaron was very heavily bearded and now shaven with make up and a dress on.
No problem for us but what is very hard is to change the pronoun when you're in a room discussing a new song you're learning.
Nine out of ten times we use she and her but the one time you forget she would correct us and this went on for a year.
It isn't easy when you've known somebody for years.
That was the first thing that sprang to mind too when I opened this thread.
If it's not, then I don't know what the significance is. If the name at the bottom of the email is Christopher, then it's a male. If it's Christine, then it's female. I can understand why someone would use it for a more ambiguous name such as Taylor where that can be male or female. So you can either say I'm Taylor, pronoun male. Or you can say I'm Mr Taylor Smith, then Mr would imply that he is male.
My ex Brother in Law now as a new partner who is 100% female to the eye and has the parts but is none binary so has asked to be called 'they & them'.
I will never meet her so it won't be a problem.