Bizarre. Humans are not the only species who menstruate, so one could easily presume they're talking about apes and monkeys, elephant shrews or bats.
And they're reducing their target audience to the one in four of us who are menstruating at any one time. Definitely not talking to post-menopausal women, are they?
Also, I just find throwaway did you knows without source or detail bloody annoying. Because while, yes, the median age for girls to get their period is about 12 and a half now, that median has actually been fairly stable for decades now. The reason for this earlier onset lies in better health, better access to food and better nutrition which together mean that today's girls reach the weight necessary for menarche to set in much sooner.
But what can you expect from a group that dehumanises women and girls like this. Each and every single company that buys into this language also buys into the destruction of women and girls as a distinctive biological and political class. That is the end result of this practice.
It's okay to accept that women and girls exist. It's alright to use our name when talking about biological functions only the female-bodied can experience. It's a dire state of affairs when organisations dedicated to these exclusively female experiences take the extreme outliers as the norm. One in 34,000 adult women have sex dysphoria. Up to one in 100 has gender dysphoria, which may or may not include rejecting her female body and/or it's functions. So 99% of us must lose our name for this small number of women, who could, after all, be easily included by additional words.
There was an article I read a while back that bemoaned the fact that only 5% of articles about menstruation focused on the experiences of women and girls who identify as trans. (I'm sure that percentage is much higher now.) It hadn't occurred to the writer that this was an at least five-fold overrepresentation of this group. Made me wonder what percentage would be deemed sufficient. I guess the answer is quite clear now...