So... anyone who disagrees with you is a zealot and you point out a specific group. There's a nice bit of objectivity.
But your scenario about the kids... okay let's have it. Your two kids are merged into one person. That means they have your children's characteristics, memories and love for you. You spend weeks with this kid, he calls you Dad, declares he loves you and it's great and despite your other two kids being gone you begin to bond.
Now you're saying you would, without hesitation, kill that kid who's begging you not to, that he loves you, when the cure is found? That's pretty darn harsh, cold and remorseless.