Humanity wasn’t facing a global zombie threat. Humans were surviving just fine before, during, and after the Nazis.
I find this kind of action to be a lot less of love and much more of obsession and competitive loving. Unless the person you “love” thinks the same way you apparently do (i/e the one you love wants you to burn the whole world or wants you to hold everything else in the world as less important than themselves), then it’s not love. I suppose it’s possible to fall in “love” with someone who would rather you murder millions of people to save them, but I’m not sure that kind of self-absorbed person is worthy of that much love.
What you seem to be thinking of is the Reality show/comic book definition of love where you don’t actually respect the desires of the person you are in love with, but would rather try to force that person into accepting your own self-inflated definition of how much you love them. If your significant other/daughter would rather you “burn the world” than let them take the chance to save humanity, I guess that’s fine. But I’d be hard pressed to “love” someone who valued themselves and their life so much more highly than what is right.
Don’t forget that Joel had already lost his biological daughter. He at first was reluctant to take on Ellie, and didn’t like being saddled with her. It’s more than halfway through the game before he starts calling her “baby girl”, his term for Sarah, his daughter. At that point, she’s his daughter, in his mind, and he would do anything to protect her, especially after having lost Sarah.
Just as a what if, let’s suppose that Ellie was indeed the biological subject that held *the *cure for humanity and the Fireflies would have extracted the cure and manufactured it successfully. What would we make of Joel’s decision?
My initiation reaction was “Oh shit,” when Ellie asked Joel to swear that what he said was true. I would have been tempted to tell her the truth - and my initial reaction, when Joel lied, was disappointment. But thinking on it some more, I have to womder whose interest would have been served by the truth.
Joel would have burdened Ellie with the knowledge that the sacrifice of her own life might have led to a cure for mankind - a burden Ellie - a 14 year old - should not have to bear.
She could go back to the Fireflies.
My own opinion is the Fireflies were dramatically over-estimating the chances removing Ellie’s brain would have led to a cure for anything. They - the Fireflies - had shown poor judgment in the past. The liberation of Pittsburg, for example, hadn’t gone as planned.
As an organization, they seemed to be on the decline. And I wonder if the remaining members weren’t grasping at straws: looking for something to justify the losses they’d sustained, and a reason to go on with whatever it was they were doing.
To me, it seemed the biggest threat to humanity were the infected, along with the uninflected killing each other. A vaccine wouldn’t have fixed either of those problems.
The group Joel’s brother belonged to seemed like a better bet for re-establishing humane, human community. The kind of place a fourteen year old girl might have a shot at growing up in a reasonably normal place.
But perhaps I’m merely justifying Joel’s actions.
I hope that Joel’s brother’s location gets notified as soon as Joel and Ellie come back that Ellie has been infected. They don’t want any witch hunts if her infection comes out after being hidden.