The user wants to interact with a bot that isn't characterized as being distinctly male or female.
The bot character is portrayed as gender neutral, which can be conveyed via the pronouns it uses to refer to itself, the tone of voice it uses, the visual imagery or iconography, etc.
Is it a problem for the user if a bot is understood as male or female? Not directly in terms of task completion and a lot of the time it may have little impact on a user's impression of an app. But the perception of gender varies, so if we want to be in full control of the impression our bot is making and mitigate risks, we should avoid overt gender coding altogether. There's also a moral imperative not to contribute to harmful gender stereotypes (for example, by aligning a subservient bot with a female gender or a powerful one with male).
Focusing on gender is just one way to think about these issues; there are many other ways in which human-like traits in a bot can cause issue. Users who align with the traits may feel like their identities are being parodied or otherwise reduced to a stereotype, and users who don't align with the traits may feel they're not the intended audience and/or that the system is designed so they're dissuaded from greater participation. Steering clear of human-like traits altogether can reduce risk and is an effective way to avoid the Uncanny Valley effect if nothing else.