This is such an incredible leap in logic.
You can say that having kids is selfish, which it objectively is (no matter if they're perfectly healthy/wealthy/on top of society or not), but also want to "build a society and world that will accept us, accommodate to us, liberate people and save the planet."
Focusing on just kids with disabilities and not every kid is fucked though, with a lot of these people in these spaces.
You straw man the position and say following the conclusion of the straw man, humanity must end based on their logic.
How isn't having kids selfish? You're not having a child for this child's sake. You're having the child for your sake.