Don't tell people they're not the label they've chosen to adopt.
I support the pro-choice argument that more abortions could be avoided through various societal changes, access to healthcare, fewer barriers to facilitating survival, and more education. I don't support the idea that the term 'pro-life' has—or should have—a certain definition. Taking someone's label from them and reapplying it to other circumstances is aggressive and disrespectful.
Self-identification is a private and personal matter. We are here only to receive people as they present themselves. If they're open to our guidance and input, we can share with their consent, but redefining terms in an attempt to invalidate someone's position is not only disrespectful, it immediately evokes defensive feelings.
It’s ok to express misunderstanding of certain positions on rights-access but assigning a label, or removing a label claimed, is a verbal attack. Pro-life people often have valid concerns that aren’t always focused around taking control of someone’s body. For example, there is concern that terminating a life, at any stage, makes it possible to terminate life—at any stage, as long as you have some kind of justification. This is a valid concern, the adoption of a pro-life position is about advocating for the preservation of life and against the termination of life. While I disagree with that position and have, what I consider, to be a strong argument against it, their logic is reasonable, they believe they’re being pro-life.
A Rose By Any Other Name...
Telling someone they are not pro-life because they have not met your definition of the term doesn't make them not pro-life. Assigning someone a label such as anti-choice is offensive. The fundamental position of pro-life people is not to remove choices but to ensure choices do not intentionally lead to or include avoidable death. To remove one choice does not mean to remove all choices. Anti-choice implies there are no choices available, and assigning that position to the movement is inaccurate.
When debating something as personal as body autonomy and self-governance, it's vital to communicate with agreed-upon definitions. Finding common grounds is how the conversation will be able to progress. Common ground cannot be reached if basic terms are not respected.
The central argument of the pro-life group is that humans have a right to life, they have a right to not be terminated for any reason. During an abortion, a life is terminated. That is a fact. Being pro-choice does not deny the fact that abortions result in termination of life, but that's a matter of medical ethics and not under the control of the pregnant person.
The fact that a group of people want to focus on one aspect of abortion—the termination of the fetus, while ignoring the exercision of self-governance by the pregnant person—is their right. That's where they are starting from. Pro-life supporters are concerned, first and foremost, with the fact that a life is devalued, discarded, and terminated, for reasons that seem unequal to the need for valuing life.
If humans are granted permission to terminate life, does it sociologically, fundamentally, devalue human life? That's a perfectly valid concern. Often this argument is alleged to be rooted in religion but approximately 13% of atheists support abortion restrictions based on morality. Assinging communal value to something is how fiat money is worth anything, it's how bitcoin is worth anything. If we remove the predetermined, communal value of human life, if it no longer has intrinsic value, in what way could that negatively impact our entire society? Why wouldn't they focus on the term life? It's the very basis of their argument and that argument has valid points.
The term pro-life is being applied to the focus on the movement. It's invasive to determine the beliefs that should fall under a certain label and then attempt to clarify for someone that the label they've adopted is contrary to your personalized definition.
A group of people have assigned themselves a label of pro-life, we don’t use that term for anything else. Why would we find it appropriate to redefine their term and then tell them they cannot use it and instead should apply a label that does not actually fit the central focus of their concerns?
Pro-choice arguments shouldn't focus on countering life arguments anyway, it should focus on self-governance and avoid relabeling.
While it's true allowing people to easily meet survival needs without barriers would naturally lead to openness and acceptance of new life, even if we had universal everything—and the unhindered ability to welcome any number of lives into ours without it threatening our ability to facilitate survival—we cannot remove self-governance. It doesn’t matter if someone is able to bear children or not, what happens with our body, regardless of what our body has contributed to, can never be a communal decision.
Consider the Legislation not the Morality
Rather than relabeling a group or denying them their focus, find a common ground. Ask how them how a right to life might be legislated.
Laws are not written in a direct manner such as, “killing is illegal”. There are specific case laws interpreted through constitutional guidance that frame our legislation. Every time a judge makes a determination, it must have been decided within the framework of the constitution. Every time congress passes law its has to be within the framework of the constitution—which is how cases make their way to the Supreme Court. If it appears to have been determined outside of constitutional limits then it’s not valid applicable law.
Considering how laws are passed, how could we legislate acceptable violation of self-governance, through non-consented access to someone’s body, via transferred consent based on the requisite that the subject of the self-governance violation, created—but then does not own—something, that was a result of other consensual activities, that could die and who's life requires access to the incident initiator's body without allowing for 1) the legalized remedy of violation of self-governance, 2) the precedent of allowable transfer of consent, and 3) the denial that one's creation is not their property to which they have inalienable rights?
Regardless of the threat of imminent death, humans don't have implicit rights to other humans. The constitution grants us the right to life, but the right to life does not then imply the right to access to the life-initiator's body.
If the pro-life movement wants to focus on life, let us not deny them that right. It's not the basis of our argument anyway.