He didn’t.
Your watching a man have his life’s work ripped away from him for something taken out of context, and used against him intentionally.
He didn’t resign the board voluntarily. You can bet your life on that.
The usual activist groups threatened to boycott.
In older, more reasonable days one could confess to a wrong without having to bow and scrape backwards.
It’s largely a Christendom problem, as I (maybe correctly, maybe mistakenly) see it. I’d like to opine that if Christendom had managed to peg Ephesians 6:9 as the verse that makes chattel slavery as we know it unsuited to a Christianized society (”givng up threatening” which leaves voluntary allegiance as the only thing that should be keeping a servant) and to say “We have sinned” — we might have a different client today. Because when one confesses sin and is forgiven, the glory goes to God. But the grudge dragged on, and eventually secular liberalism was credited with the final removal of undignified treatment of black people. But secular liberalism was the gift that kept on giving, and it gave us abortion and gay marriage and now gives us the worst screeching at Donald Trump we have ever heard. There shouldn’t have even BEEN an occasion for a Rosa Parks incident. I confess, socialists were perceptive there for their opportunity.
But anyhow that’s all 20-20 hindsight now. The only thing that will save the modern scene is a resurgence of faith that repudiates at least certain old ideas in the name of bible wisdom. The obvious evils, yes, but also there are more mea culpas to be made, to God in the hearing of man as a witness.
And I’d like to posit an observation that “giving up threatening” is an awfully hard thing to do in general. In a society where both the conservative and liberal elements prize the idea of making perceived needful things happen at gunpoint (though under different circumstances to different ends) we’ve forgotten the capacity of Holy Spirit to persuade in different manners. Was it mere high minded puffery that warned even Old Testament Hebrews not to “trust” the “arm of flesh”? If we want to recapture a Christian mindset, we have to think about the place and nature of peace as well as war.