Both of these articles phrase very nicely the reasons for my dislike of female-gendered assistants.
"The late Stanford communications professor Clifford Nass, who coauthored the field’s seminal book, Wired for Speech, wrote that people tend to perceive female voices as helping us solve our problems by ourselves, while they view male voices as authority figures who tell us the answers to our problems. We want our technology to help us, but we want to be the bosses of it, so we are more likely to opt for a female interface." [1]
"According to some sources, the use of female voices in navigation devices dates back to World War II, when women's voices were employed in airplane cockpits because they stood out among the male pilots. And telephone operators have traditionally been female, making people accustomed to getting assistance from a disembodied woman's voice." [2]
The predominance of female voices is based (at least partially, the biological argument is certainly interesting) on history and societal norms that place women beneath men in competence and authority. Thus my dislike comes from a desire to get rid of these subtly ingrained social ideas of male/female authority/submissiveness. The tech world has a far-reaching influence, so I think it needs to be conscious of the implications of choices like the "gender" of an assistant.
My personal preference is for a completely gender neutral interface, because I want to treat my computer like the tool that it is and not like another human. I think the best course of action is to give the option and let the user choose which they prefer.
The reason I called out this instance is because it goes too far. Yes, I can rationalize that people have a preference for female personalities for a variety of reasons, but the author of "Sarah" has blatantly sexualized a programming tool. This makes no sense to me. Especially as a publicly available distro. (The quality is definitely wonky for other reasons, but that is not an excuse). This extreme case reflects on the less egregious things I dislike about gendered computers in general.