*You* are the future generation of your ancestors. I assume you would not have wanted to live in a universe when humanity was wiped out aeons ago, or left to some Mad Max existence. The people making that argument do so from the luxury of not having had many ancestors that held such misanthropic beliefs.
I would ask them to contemplate Kant's https://en.wikipedia.org/wiki/Categorical_imperative
This is a thought experiment where we consider the ramifications of holding this belief. In a universe where this belief is held, your existence may be thoroughly miserable. Would you accept that? And even if you did personally, on what basis do you have the right to make this decision for everybody else? The rational and moral behavior is for you to decide your own fate and leave others alone.
> This is a thought experiment where we consider the ramifications of holding this belief.
If we are waving away the natural laws of the universe (which we must for the hypothetical to be possible) than the consequences can be anything anyone in the sevate chooses them to be, because there is no longer any rule between cause and effect.
We are not waving anything away. If you mess up the planet, you will be worse off and cursing your anti-natalist ancestors. Antinatalism negates itself on a timescale longer than a generation. It is anti-Darwinian. We exist because such idiots already killed themselves off, or others smacked some sense into them.
>I assume you would not have wanted to live in a universe when humanity was wiped out aeons ago, or left to some Mad Max existence.
But if that had happened, none of us would have been born to care anyway.
I'm not arguing for antinatalism, but this seems like a strange argument.
> I assume you would not have wanted to live in a universe when humanity was wiped out aeons ago
I am pretty sure it would be impossible for that to occur, unless you are talking to a non-human (in which case they very much might want that.)