CHICAGO (CBS) — Facebook has a strict policy on nudity and sexual content on its site.

But did the social media giant go too far when it censored a historical article?

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A Chicago lawyer thought so and is telling his story exclusively to CBS 2’s Jim Williams.

Attorney Alan Mills has long fought for social justice, for the poor and for the rights of prison inmates. For Mills, Facebook is a megaphone. Consistent with his passions and with an eye on migrants held along the U.S. southern border, Mills last week posted an article on concentration camps after the Civil War.

In that post, a photo of freed African American slaves. He then got a message from Facebook:

“Your post goes against our Community Standards on nudity or sexual activity.”

Facebook removed Mills’ post.

“I was amazed. I could not believe. There was absolutely nothing sexual about this picture. There’s absolutely nothing about nudity in this picture,” Mills said. “It was starving human beings.”

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Managing its content has been a daunting challenge for Facebook. The company has been severely criticized as users post videos of murders and other gruesome acts.

On Tuesday, Facebook has thousands of workers — so-called moderators — combing through questionable posts, keeping many off the site. Several moderators said they’re suffering from PTSD after watching millions of distressing images.

“Which had to do with a lot of violent, sexual solicitation. A lot of torture. A lot of abuse with minors,” said former Facebook worker Shawn Speagle.

“I think it’s a tough job to do. But there’s no alternative. And somebody has to be the one take down the stuff that shouldn’t be there,” Mills said. “But not this one. This is absurd.”

Mills appealed the company’s decision and got a new message this week: “Your post is back on Facebook.”

“I think everybody should fight back when they have the opportunity and ability to do so,” Mills said.

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So is it a worker or a computer program that flagged Alan Mills’ post? CBS 2 reached out to Facebook to find out but has not heard back.