There’s nothing “illogical” about noting the fact that, once a person has been murdered in the womb, he will never be a teenager, etc. Once people are murdered, they stop getting older. Society has to do without their ideas, labor, beauty, creativity, etc.
And society has to suffer the negative effects of having millions of people walking around suffering from the guilt of having murdered their own children. This has a very negative effect on society, because people who have sunk into despair by murdering their own children, are prone to sink into despair about other matters. A society that suffers from despair on a mass level is going to suffer more anxiety, depression, violence, etc.
Mass despair is the main reason Europeans are going to be extinct in about a century, because despair is the opposite of courage—and courage is what it takes to marry, have children, love those children, etc.
This guilt is the reason for the extreme antogonism of the left towards pro-lifers. Even within the Republican party, there is intense bitterness among the "country club" Republicans towards grassroots conservatives over this issue.