If conservatives were really serious about the slavery/abortion analogies, particularly about the notion that abortion is equivalent to murder and therefore violence is theoretically justified in response, you’d think that there would be a lot less “Confederate History Month” going on and a lot more celebration of Nat Turner and Denmark Vesey. Conservatives have gone as far as to adopt the Dred Scott decision as a kind of abortion dogwhistle, but I think there are a few reasons why people who actually tried to resist slavery through violence haven’t been adopted by the anti-abortion movement.
One is obviously the conservative tendency towards lionizing the Confederacy. Celebrating treason in defense of slavery makes it hard to celebrate rebellion against that same system. Another is that the embryo/black people comparison breaks down when you think of black people as actively, even violently, resisting slavery as opposed to inactive victims in desperate need of rescue by whites. That conception is patronizing and historically inaccurate when applied to blacks during slavery, but more or less accurate when applied to a fetus in the sense that a fetus can’t actively assert its own personhood.
I also just think that conservative ethnocentricity makes it difficult for them to celebrate someone like Turner, who killed a lot of white people in pursuit of freedom.

