""I'm now being really judgy about the person who sent it, I assume they are male, but they have an unusual first name,""
My first assumption would have been that they wasn't from UK origin.
I have relatives in Africa, my Dad was from SA and I cannot convince them to not use Lady, I'm also called Auntie (nothing more) by my younger relatives friends (as a mark of respect), which I'm obviously fine with, its Cultural.
I have an issue with Spokespeople, Lawyers, Top Officials not using acceptable language, which you see a lot on Television, when there has been a gang rape etc.
My DD managers people from all over the World, in Social Care roles, they have to have this subject, in the ongoing training.
The use of Language is important, but some people aren't educated on what and why they should use or not, some phrases, so you shouldn't initially get insulted, just explain.
Then there is allowing for Cultural difference, which the OP should be well used to, working worldwide. I'm sure if a conversation took place about disability, for example, the Women the OP is helping out of poverty, across the World, would use unacceptable terms.