Ok, so what? Both you and you rival have something to sell. If I don't buy it from you, I buy it from your rival. Let's face it, the Europeans created a greater demand for a product that the natives were already providing: Slaves. (no disrespect intended by the word product, just an analogy).
> *"ignoring your own source saying that it isn't clear chattel slavery was practiced in the area"
The moment the natives the sold those slaves, even if they weren't chattel slaves before (which I agree with you, was not clear), they started practicing chattel slavery. That's just the definition of it.
In a nutshell, Europeans didn't turn that people into chattel slaves, they where turned into that by the other natives that enslaved them.
> "Yet you ignored the parts that didn't, like the ten percent of the population part."
Yes, the 10% that only occurred for a short time compared to the rest of the all Europe and because you keep accounting for people passing by than only spent there some weeks (i.e. the slaves waiting to be sold).