The goal of a tool is to be used by someone, and if the interface is the voice that the user can interact with it makes sense that it should ultimately be up to the user's preferences how the voice will sound like.
I see the fact that they're aiming for gender-neutral voice as yet another ludicrous attempt to advertise their advocation for inclusiveness which, while I'm in favor, I think has manifestations that go well past benefiting the original intention. Examples: Main over Master branch on git repositories, Latinx, removing "blind playthrough" on Twitch.tv because it indicates ableism, and so on.
I don't mind having some voice selections out of the box, but if they're gonna restrict my options and ability to change them to fit my preferences then I do mind. Our primal brain (lizard/monkey, or whatever tag you feel like assigning) will always perceive voice interaction as "talking to someone else", so why not just let the user choose who they talk to? It's a tool, for the user's needs. There's no need with appropriate ascribing of a gender to a tool, because it's not a human or anything living.
But I think the default voice and your first public demos could be gender-neutral these days.