The fact that you are even aware of those cases, makes a statement in and of itself. The U.S. does not condone this and seeks to stamp it out. Sentences for those who have facilitated this, are severe.
Sadly, you didn’t mention other places around the world where slavery is not only accepted, but is a thriving business.
I provided links to some of those in 18 if you’re interested.
Since the "IRS as slave master" concept is a domestic theme I elected to keep the focus accordingly domestic.
For the record, I'm aware of the status of the slave trade outside our borders, and don't advocate waiting until we have our own house in order to aggressively combat it, but I'm strongly of the opinion that we ought to fight this more aggressively within our borders than we do beyond them until the scourge is eradicated here at home.