Since she seems surprised about this, I wonder if the author has had any social media profiles at all, because these kind of responses come through every channe

Since she seems surprised about this, I wonder if the author has had any social media profiles at all, because these kind of responses come through every channel — be it website customer support chat or Facebook messenger or chat sites or matchmaking/dating sites or even plain old IRC. All that you need are to have a female sounding name and (if the platform supports it,) a picture that looks like a girl or woman. It used to be that such names would get private "asl?" (standing for "age, sex, location?") messages before social media came into existence. Any mention of "f" and a somewhat younger age would get lots of messages of different kinds — enough to prevent real girls/women from using female sounding names or nicknames online. As for anonymous nicknames or handles, I'm all for it. While people who want to say nasty stuff will do it even with their real names attached to it (there are many examples from Facebook), the negative effect that real names (or forcing them) has is two fold — it increases harassment for girls/women (and some others who are normally discriminated against), and it makes people censor themselves more than they need to (more so in environments like Facebook where most people have one identity to interact with different circles and relationships in their lives). The Internet was always a place to use self-chosen nicknames and handles, and the kind of community shapes the interactions more than the mere ability to use a nickname/handle. As someone who values privacy and is strongly opposed to profiling, censorship and surveillance, I wouldn't want a world where anonymous/pseudo-anonymous communication doesn't exist