This is a confusing one to me, honestly. The act of giving birth is so closely tied to the genetic and biological definition of one's sex I'm not sure why it would fall into the same category of terms that can be offensive based on the gender one associates with.
It's more a matter of precision than offence. Trans men who give birth aside, there are lots of mothers who didn't give birth (adoptive mothers; lesbians whose partners give birth). 'Mothers' simply isn't the same category as 'people who have given birth'.
Plus, if what you're talking about is the experience of pregnancy and giving birth, then it makes sense to focus on that, rather than on the much wider experience of motherhood.
To me, it's more confusing that some people insist on using less precise terms because they find the idea of inclusivity offensive.
The dictionary definition[1] is female parent so I'm not actually sure that the term mother would be exclusive of adoptive parents or lesbians who's partner gives birth. But looking back at it this would likely exclude trans men who give birth so I may in fact need to extract my first comment.
We're 100% in agreement on the offense issue though. I don't get why anyone is offended by what someone else prefers to be called. Take the politics out of it and that's like being offended that someone says their name is Steve when you absolutely refuse to believe they are called anything other than Bill.
