Another reason Pluribus works as well as it does: precisely because it's a lesbian love story. If the hivemind lead was a man paired with an immune woman, the hive would come across as overtly aggressive. If the immune lead was a man, it would look similar even if you know the dude is literally up against the whole world - on screen he'd still look like a scary man yelling at an innocent-looking, acommodating woman.
However you flip it, it would LOOK like a very overt form of abuse. The viewer would inevitably worry about either character's physical safety, whereas it's essential for the story to focus on the emotional safety.
As it is, we never worry about Carol punching Zosia and frantically running away. We never worry about Zosia causing Carol bodily harm to get her to comply. The two being at the same level in terms of appearances and physicality is what lulls us into perceiving some semblance of equality between them. And we the viewers have to have this illusion of equality for this to hit where it ought to.
Edit: Would the story work between 2 men? I have no idea and I'm the last person on Earth to ask.
Edit 2: I'm also not saying that having a man in a scene necessarily leads to a threat of physical violence, but moreso about media-speak and how we might be wired to interpret it visually. I'm assuming the majority of my audience here is queer, but it needed to be said anyway.