I thinking calling it "human sacrifice" is needlessly emotive, therefore unhelpful; and inaccurate. Acts of sacrifice are acts of religion rendered to deities, usually by cultic personnel such as priests, or at least by agents acting as priests.
The deliberate destruction of unborn human conceptuses (of any stage of development) is not:
an act of religion
rendered to a deity
by cultic personnel.
Neither is it a "holocaust", for a holocaust, is a "whole burnt [offering]" - a species of sacrifice. Sacrifice is (among other things) a visible action or proceeding, performed as an act of religious cultus. The essence of such an act, at least in the Biblical world, is the surrendering (often by inflicting death) by the sacrificing agent of a person, animal, or thing, to a deity; with the result that what is sacrificed is no longer available for "profane", "worldly", "everyday" uses.
Self-sacrifice in battle has some roots in the religious act of sacrifice. When in 340 BC the consul Publius Decius Mus "devoted himself and his foes to the
Dii Manes and mother Earth to give his army the victory in the
Battle of Vesuvius, in which he was slain and the enemy annihilated", he sacrificed himself in both the religious & the extended senses.
Publius Decius Mus (consul 340 BC) - Wikipedia
Voluntary religious & military self-sacrifice like that could hardly be more removed from what happens during an abortion - another reason for not calling abortion a "holocaust".
Acts of sacrifice, whether partly externalised by performing an outward act, or purely invisible and internal, are pleasing to God, from a Christian POV. That is established by the use of a metaphor for sacrifice in Romans 12.1, to say nothing of the place in Christianity occupied by the Death of Christ, which is regarded, from the NT onwards, as a sacrifice. It is hard to see how abortion, the intentional destruction of the unborn, which has been condemned in Christianity since at least the 2nd century, can be pleasing to God - another reason not to refer to it in the language of sacrifice.
Misusing or over-extending religious terminology that has a definite and clear meaning tends to unfit such terminology for its function in describing (in this case) acts of religious worship. The word "Christian" is another word that has been over-extended and made almost useless for its original semantic function.
For these reasons, I think the word "Shoah', meaning "calamity", is in every way a far better word for the systematic and prolonged massacre of the Jews by the Third Reich than the word "holocaust". What happened was in every respect a calamity.
And the act of abortion, with its many harmful effects, STM to be much more a calamity than a holocaust.