They do have a say in whether or not they want to raise it. No one is demanding that they be active and attentive parents. They’re just being told that they need to help financially support the child that they had an active hand in creating.
Until UBI and true test tube births are a thing, pregnancy will always put all of the risk on the birth giver. This is inherently unfair. In order to even out that risk, the non-birthing parent should be required to support the child to a minimum level.
Granted, UBI and universal support would entirely negate the need for this discussion and it’s what we should be working towards in the long run, but we can’t just… not support the kids in the mean time.