According to the last paragraph of the article entitled "Escape From Slavery—Then and Now" (WT#2, 2017)
Jehovah God felt grieved by the harsh treatment of Israelite slaves in Egypt; he must feel the same way about similar injustice today.
If you call modern slavery "injustice", wasn't the slavery during Moses time also "injustice"? And how else can you call a God sanctioning such slavery if not unjust?
But according to Organization's crooked logic only Israelites' slavery in Egypt was unjust, as well as modern sex slavery. Sex slavery by Israelites, under Moses' Law, is not considered unjust.
How utterly gross hypocrisy! This organisation is making me sick.