I also must disagree.

Holding the "a permanently comatose human is not a person" and a "a fetus could be a person" aren't incompatible. The first statement presumes a definitive state to body where as the second statement holds a potential.

A significant portion of the population might agree, but it isn't all. If it isn't all, there's disagreement. It bears reminding, witch hunting was consensus at some point. I think this serves as a sufficient counterproof for majority consensus as a source of objective truth.

I'd like to press on this unnaceptable callousness: if it's objectively proven that newborns lack sufficient potential for personhood, why would there be an issue with post-birth abortion? It's not like the "conservative" approach here is victimless, the guardians of the newborn will have to bear a responsabily they have no duty to, infringing on their right to live. And infringing on this right is as unacceptable as it can get. Of course, this is presume an extreme pro-choice position is true, which I personally find unlikely.

In the end, I find that the majority of pro-choicers (not saying this includes you) aren't much better than religious pro-lifers. Most of the time, there isn't a deeper consideration beyond "my body, my rules" or "the law says humans with at least X age are people". Sometimes, it's even "evil misogynists want to enslave woman into baby factories." At least, the religious pro-lifers are transparent about being about their creed. These pro-choicers stiffle discussion under the pretense of legal consensus, which makes discussion harder.

But, because question of abortion, as you have stated before, is directly related to when personhood emerges, it's also related to the origin of personhood and, going further, human rights themselves. As such, I think there's less consensus on this topic, most just haven't given the proper consideration - we can kind of see it already: not every pro-lifer is against abortion in cases of rape/possibility of mother's death, and some pro-choicers are very strict: a fetus only becomes a person after being born.