John Piper has come under a great deal of criticism, justified criticism, as he sought to defend his ideological hero, Jonathan Edwards, for owning slaves. Numerous articles have been written about John Piper’s attempt to explain away and/or understand Jonathan Edward’s owning of slaves.
In the end, many conclude that John Piper is a dogged theological hero worshipper of Edwards, and more committed to the Calvinistic ideology (which is inseparably linked to a person like Jonathan Edwards), than being biblically principled and simply condemning Edward’s owning of chattel slaves. 
In some sense, Piper’s defense of Edwards is not a surprise. That’s what happens when you become a theological ideologue, a person who is so committed to a theological position, movement, approach, trend or fad, that you become blinded. You can no longer see what is obvious with any biblical clarity –(John 9:17). Piper’s theological and ideological demeanor has reflected that tendency for decades, as he has also become one of those heroes to whom others exalt and cling. Now, some will be unwilling to denounce Piper’s defense of Edwards.
Today’s theological landscape is pockmarked with the same obstinacy (or “perseverance”). Ministry leaders and pastors, who hold fast to theological ideologies and personalities, with the same doggedness, become grimed by what they ought to have quickly thrown overboard and denounced — chattel slavery. Today’s obvious and contemporary example of that reality — John Piper!
. . . .
1. “Edwards lived and died a little before the abolition movement gathered momentum in Great Britain and significantly before the issue was tackled head-on in the States. However, I don’t agree that his actions in owning slaves can be justified on the basis that he was a man of his time. He was a contemporary of those who were becoming awakened to the issue, such as Wesley, Wilberforce, Newton, and Clarkson (the original “Woke”). Furthermore, their whole argument was that it is obvious in Scripture as well as by way of tradition, experience and reason that owning and trading in slaves is wrong.
So, I think Piper’s wishful thinking whilst understandable is unhelpful. We would do better to say simply that Edwards was wrong on this. Indeed, if Piper is right and Edward’s theology helped convict Piper on these very issues, then that makes the situation worse, not better. Edwards own words condemn him on this issue.
We need to be ready to recognise that those we consider heroes were men and women with feet of clay. They sinned, they failed, they were far from perfect. Those who owned slaves and justified slave ownership were wrong to do so. Their place in Christ’s kingdom is not based on a rose-tinted assessment of perfection but on faith in the God who forgives and justifies sinners. Our response should be at one and the same time to recognise that slavery and racism are inexcusable, to turn our backs on wishful thinking and instead point people to the forgiving power of the Gospel.” — https://faithroot.com/2021/08/19/john-piper-on-jonathan-edwards-and-the-slave-trade/
A FEW of the many articles on Piper’s attempt to defend Jonathan Edwards’ owning of chattel slaves.
Christian Leaders React to John Piper’s Thoughts on His ‘Hero’ Who Owned Slaves
Jonathan Edwards and His Support of Slavery: A Lament