Let’s keep it simple; rape is use of your body without your consent. In particular, the use of those parts of your body associated with your sex. Another being’s use of your uterus w/o your consent fits pretty much all of the legal & moral requirements to qualify as rape. Terminating a pregnancy because it is unwanted or in some regard unsafe for the mother is not appreciably different from killing a rapist. The intent of the violator is irrelevant. What matters is the desires & consent (or lack thereof) of the person being violated.
Most sexual rape is over in a matter of minutes. The fact that the violation of an unwanted pregnancy is continuous over a period of nine months only adds to the burden against the violator. Many states with “stand your ground laws” only require the perception of potential harm in order to justify “killing in self defense.” Texas has now declared that a woman with an unwanted pregnancy no longer has the right to defend herself & anyone who would help her to defend herself is subject to lawsuits.
Preventing the use of your body without your consent is protected by a large body of law. Killing in self defense is not murder. Neither is abortion.