Let’s change your argument a little
Of course I am not in anyway condoning slavery, but I am a realist.. We are hamstrung by the laws that are on the books, and until the culture has reversed its opinion, the only way to halt the option is to hold them solely responsible for their own actions, and to slowly limit the methods that any other option to freedom is lawful, and restricted..
Here’s a better idea. Just state that it is wrong to kill children and not accept a compromise because killing children is unacceptable. Draw a line. It’s wrong to round up Jews and kill them, it is wrong to enslave people and it is wrong to kill children simply because one person doesn’t want the child around.
Hopefully, at some time in the future, pro-aborts will be viewed with as much disdain as pro-slavery people are from today’s vantage point.
I point that out to pro-aborts - that the main argument is the same, that a certain segment of humanity is less human than another, and therefore has less rights.
Pro-aborts, future societies will DESPISE you.