Clever, but if you put slavery on the scale of indentured servitude, or even employment and debt service in general, the analogy breaks down :)
At that point, we’re talking about reasonable restrictions and expectations on property ownership, and debt service, which reasonable people can differ on what is predatory lending, or immoral usury, without immediately dispensing with private property rights or lending for interest.
I think the important thing to focus on, once you’ve gotten past the “is a zygote a human” and “is homicide sometimes the lesser of two evils”, is how to reduce the need to make that decision between the lesser of two evils. This includes strengthening families, shaming promiscuity, and working towards, as it was once said, “safe, legal, and rare”.
We may never agree on where the line should be drawn, but I think it’s important for everyone to consider that rational, well meaning people can disagree on the placement, and still work together towards avoiding the lesser of two evils choice.