Because a piece of software is usually, and grammatically correct as far as English goes, referred to as it
There is nothing grammatical about it in English. In practice gender in British English generally specifies the actual sex of the object, except when the object doesn't have a sex in which case it is merely conventional. Things that are sufficiently important to us are anthopomorphized and this a social and cultural process rather than a strictly grammatical one. Ships are conventionally female in British English, so are cars in some circles, but there is nothing grammatical about it. Similary my wife refers to her Android tablet as he, and he has a name; however the name is ungendered in modern British English while it is a female given name in Ancient Greek.
This is a piece of software, yes, but it is a piece of software portraying a fictional female character. "She" makes perfect sense in this case, not to mention all the other instances where gendered pronouns are used to refer to inanimate objects. I think this complaint is making a mountain out of a molehill.