> If you call indentured servitude slavery

You’re being perfectly accurate; indentured servitude is consistent with both historical understandings of slavery and modern legal definitions; it was certainly distinct from the particular form of chattel slavery that was popular for a few hundred years and fell out of fashion in thr 19th century, and it is useful to be able to distinguish them since they overlapped in time and space, but that particular form of slavery was not the historically dominant form, itself, and it doesn’t make sense to narrow the definition to that particular form.

While, certainly, that form of chattel slavery was the most immediate concern for, say, American abolitionists, I think they would see it as badly missing the point and not actually abolishing slavery if indentured servitude had been restored to replace chattel slavery.

Yup, not the dominant form.

However I found a curious tidbit the other day; the 1619 ship had indentured servants not slaves. Not to belittle their plight, as they were de facto slaves as soon as they got on the ship.

American abolitionists very much understood that chattel slavery wasn't the only form of slavery. The text of the 13th amendment indicates as much.