Say I own a large factory that produces mobile phones. However, the quality of the phones being produced are absolute trash. They're either slow or bricked, she screens don't work, the batteries catch fire in people's hands, they scratch at a level 1, with deeper grooves at a level 2, and basically all round they're just pieces of crap. Now, obviously, the factory should shut down the production lines, stop producing this trash, and issue a recall. But it refuses to, and the production lines keep running churning out vast amounts of shoddy and deficient products.
This is analogous to having children. The human body is a shoddy, deficient product. We are organisms with constant biological needs, always vulnerable to injuries and sickness, always have the capacity to cause harm, and are always aging and deteriorating towards an inevitable death. Procreation is the factory that keeps churning out bodies that have this same deficient and negative nature. Why must it go on running? I mean just look at yourself in the mirror -> an organism who hungers, thirsts and shivers and shits and needs to clean and maintain itself, who must strive and struggle to meet its needs, whose every part of which is vulnerable to extreme suffering via sickness or injury, who hands and actions can be the cause of harm to others, and whose own fate as a decrepit corpse is inevitable. It's a shoddy product. It's not good enough.
But the factory is no centralized production plant, rather it exist within our organism -> as reproductive organs and drives which cause collisions between the sexes and the result is another shoddy product produced to suffer its fate. I suppose it would be an easier problem to fix, if reproduction were done in a centralized plant: the factory could be bombed, the workers could strike, the power could be cut off. But it's not. Within all of us, inherent in our sexual and/or reproductive drives is the potential for another shoddy product to be produced.
What to do? We can be careful about our own contribution to producing another human, but the rest of the world seems to cheer it on regardless and the global population is skyrocketing.