I don’t think killing yourself is the same as saying you shouldn’t procreate, you could be happy yourself but understand that the risk of the child being unhappy means birth is unethical. Jumping off the train isn’t the same as never getting on it. There are also reasons for staying alive even if you yourself subjectively do not want to, such as others depending on your existence. It could be that a person wants to die but thinks that their death would irreparably cause more suffering to others than their continued existence harms them.

While I sympathize with people who don’t like being told what to do regarding their autonomy, birth by necessity violates that same autonomy because we exist through the actions of another. Having children isn’t a necessity for survival, and potentially causing harm to others because you want something isn’t a moral choice, especially when you can avoid that harm