Just to apply reductio ad absurdum to the anti-natalism argument: If there was a virus that would prevent all animals and humans on the planet from reproducing, leading to the quick extinction of all consciousness, would that be a moral good?
I'll also mention it's important not to confuse anti-natalism w/ pro-mortalism.
The better question is why aren't you having children as often as possible if you think life is worth while. On average any fertile couple can produce around 12 children, if you're not on track to have that number of children but think that life is so grand then why aren't you?
The difference between you and me is that you're ok with not creating 9 to 11 lives during your reproductive age, I'm ok with not creating 12.
I'll have enough children to sustain humanity and keep consciousness in the universe, having 2.1 children still means a potentially infinite line of descendants, so no reason to have 12. 12 would decrease the average well-being, while having none would decrease it as well.
Also, I would be interested what you think the crucial difference is between not continuing to live and not being born.
It is the difference between killing two children and deciding to not have 10 extra ones.
So I ask you again, would you prefer not to have been born? And if yes, what's your argument for continuing your own life?
People that exist have wants.
I exist, yet the dozen other children my parents could have had don't. You can ask them if they want to have been born, but they don't have an opinion on the matter.
Which part of that do you have trouble with?
That's a pretty weak "gotcha" as well.
The reason I have had 3 children instead of 12 is because it balances my interest and desire to be a parent with the work/cost of doing so.
I doubt anyone's decision to reproduce is centered around bestowing the maximal amount of meaning to the universe.