It is a conditioned choice, not a free one. And as you said it comes with a cost.

Not just that, when women make other choices (like being child free), they would be criticized and blamed for low birth rates.

And it is the complains by men to women who have no children what shows how that choice is not really free. I mean, if they choose to penalize having children, it follows that they should accept the consequences (lower birth rate). But no, they complain anyway...