Brazil’s definition of slavery is much broader than the one you’re thinking of.
> In Brazil, slavery is defined as forced labor but also covers debt bondage, degrading work conditions, long hours that pose a risk to health, and any work that violates human dignity.
"Generally" could mean what you mentioned, or it could mean straight slavery - as the article said there is not good stats. Forced labor is prevalent in many industries, using the US definition of slavery: https://www.dol.gov/sites/dolgov/files/ILAB/ListofGoods.pdf Your original claim was that decriminalizing drugs would prevent this sort of behavior. I think the linked report shows that is not necessarily true.
> In Brazil, slavery is defined as forced labor but also covers debt bondage, degrading work conditions, long hours that pose a risk to health, and any work that violates human dignity.
https://www.reuters.com/article/us-brazil-coffee-slavery/pic...
Their “slaves” are generally people with poor alternatives with a side of government corruption/ineptness.