I've never heard of anyone suggesting that "herstory" be substituted for "history" in the English language, or even claiming that "history" is a gendered word or concept.
"Herstory" is a pun. A clever way of expressing the fact that women have, in fact, been excluded from the stories the human race tells itself about itself. To put women back into those stories, there is "herstory".
I'm sorry, but when you say:
Are we now going to separate histories for men and women? The so-called word, herstory, is a silly attempt to purge gender from rhetoric where it doesn't even exist.
I just hear you making things up, unless something very odd is going in the halls of academe in the US that I'm not aware of.
http://en.wikipedia.org/wiki/Herstory
Herstory is history written from a feminist perspective, emphasizing the role of women, or told from a woman's point of view. It is a neologism coined in the late 1960s as part of a feminist critique of conventional historiography, and refers to history (reinterpreted as "his story"

written from a feminist perspective, emphasizing the role of women, or told from a woman's point of view. (The word historyfrom the Ancient Greek ιστορία, or istoria, meaning "a learning or knowing by inquiry"is etymologically unrelated to the possessive pronoun his.)
... During the 1970s and 1980s, second-wave feminists saw the study of history as a male-dominated intellectual enterprise and presented "herstory" as a means of compensation.
The term, intended to be both serious and comic, became a rallying cry used on T-shirts and buttons as well as in academia.
In feminist literature and academic discourse, the term has been used occasionally as an "economical way" to describe feminist efforts against a male-centered canon.
You are tilting at straw windmills, from what I see.
There may be arguments against the concept of "herstory" (see further in that wiki article), but acting as if there is some serious movement to replace the word "history" with the word "herstory", that's just, well, silly.