We've ben over this multiple times but fetal homicide laws exist separate from normal homicide. If fetuses were legal persons there would be no need for fetal homicide laws, you'd just charge the person with double homicide. The law does not recognize fetuses as people generally, only when instructed to in specific instances. Your example illustrates the opposite of what you're alleging.
The exception proves the rule. It proves you are murdering human beings through abortion: theonly genuinely morally justifiable case would be in the case of life threatening situation to the mother.
As is the case with self defense laws. One day the law will accord with what is actually true, namely, that a fetus is a human being completely deserving of the same natural rights the rest of us hold.