You said it was unconscionable to have children, so by your metric no-one should have children. If you’d like to walk that back and concede you were being hyperbolic feel free to so!
Again, I agree with you, I agree that a smaller population would be a Good Thing. But the shock to society/civilisation of even a 50% reduction in birthrate could be just as savage as the impacts of climate change. We’d be back to encouraging elders to commit suicide rather than being a burden on society.
I also think that there’s not a lot of point to civilisation if we aren’t aiming for people to be happy and fulfilled, and for a lot of people raising a family is the biggest contributor to their happiness and fulfillment. You dismissing that of hand and judging those people for wanting what makes them happy seems pretty mean and uncaring.
The existence of theoretical solutions is very different from the probable solutions given the various complex competing interests and short-sighted myopia dominating the majority of decision makers.
Again, I agree! But I do think that the existing technical solutions should be proof against the despair that you are peddling.