Diversity questions aside, some given names are ambiguous. Some names are not, but may have different (assumed) genders depending on the language. In those cases it may be helpful to add a "Mrs"/"Mr" or similar, just to save people the embarrassment of addressing a woman as a man or vice versa. And isn't a "Mr"/"Mrs" a sort of pronoun spec as well? You're saying "use the usual pronouns for females/males".
Follow up question, given that women have been in the workplace for 50+ years, why wasn't it an issue back then, and only presented itself now?
Now they do. The solution was always available, of course, but there wasn't much pressure to implement it because it was merely a nuisance. It's more than a nuisance for people whose pronouns change or whose physical appearance leads people to the wrong pronouns. So they decided to implement the solution, along with people who are sympathetic to putting for the minimal effort to help them.