Excepting cases of rape and incest, you chose to have sex, deal with it.
What if the partner was lying about contraception?
What if somebody wasn't educated on the consequences of sex?
What if the mother was brought up in an enslavement society that taught her from early childhood that women should to as they are told and spread their legs when told to? (Basically all societies on this planet until a few decades ago)
What if somebody was emotionally coned into getting a child and the abandoned by those just as responsible? (Mostly men abandoning women, except in societies that ensure guys don't chicken out and have more-or-less equal rights)
What if somebody is using a child as an excuse for a free ride and as a vector for irresponsible behaviour?
Aside from that, I'd like to hear from you if it's better to keep the child and have it born into misery and/or abadoned into foster care or rather ensure that someone who doesn't want to have a child or technically can't handle it can abort (up to a medical resonable point that is).
Bottom line: Your reasoning looks so neat and simple, but it has holes so big as to drive a mac truck through them. Ergo: Wrong. You should reconsider your maximes on this.