Because it always goes on somehow.
Young couples who love each other and want to start a family see the glass half full and hope that the future will be good.
It has always been like this, children were born at any time, no matter how bad it was.
I would probably still choose to have a child today.
To entertain the adults.
Others don't have to justify the fact that they want children, just as you don't have to explain the fact that you obviously don't want children.
This is called species conservation and is deeply anchored in our instincts. If that weren't the case, humanity would already be extinct.
Many people want to have children, although I can'tz understand but that's probably the reason. They want a child and don't care about the rest.