Besides, modern times have allowed us to avoid raising children if we don’t want to. We just don’t have to wait until the baby is a fully formed human and born from its mother’s womb to make that decision. In practice it may feel better to do it that way, but the basic effects are the same.
Naturally a society which practices abortion but not abandonment would think so. But in both cases the function is essentially to provide a mechanism for infanticide to a society in which infanticide is prohibited (or rather, abhorred). There is a rationalization (for us, that the fetus isn't a child; for them, that the child is not actually killed, its life being turned over to the gods or to fate) but the rationalization is secondary to the fact that the act leaves the parent within, or on the border of, the normal workings of society instead of outside them altogether.
Yes, but in the Roman world they left them at trash dumps and if they didn't simply die of exposure they were free for anyone to take as slaves. So I think we're still doing a bit better.