Should he have been fired?

How do you rationalize fixing it? Keeping him at his post amidst a staff of bigots who wouldn't tell him any different, and allowing him to keep spreading a message of hate?

You are right in everything in your first sentence, but how to solve this problem? I'm more curious now from a discussion standpoint.

I'm not trying to fix it. I'm simply pointing out your response doesn't accomplish anything positive, for anyone. It won't unmake what he said. It won't change how he thinks/feels. It won't change anyone who agrees with him. It won't satisfy the people who feel wronged for more time than it takes the next thing to piss them off. I recognize it as nothing more than his opinion. If I had any degree of vested interest in his claims I'd answer them the traditional way; In an editorial/commentary rebuffing each point I had issue with, using my own factual verifiable sources to debunk the prejudiced and inaccurate ones so that a reader could make their own determination and the author could consider the additional information/views.

Keeping him in his job obviously won't fix him, but more importantly removing him from it won't either. It's just punishing him for the sake of having an unpopular view.
In order to "fix" him, you'd have to establish exactly what you consider a successful resolution. If the goal is for him to understand his view is unpopular, or that he's mistaken, beating him up isn't going to accomplish that, if anything it'll only more strongly associate for him his belief that affirmative action has gone too far.

I'm disappointed in you declaring that a "message of hate". It's a message of ignorance, prejudice and fear perhaps, but certainly not hate. People like yourself projecting their own issues on to this author and blowing it out of scale are just as misguided as he was. What would it take to change your perspective? If you want to change his, you'd have to consider it from that angle. You're interpreting his motives, and to some extent even his very meaning, based on your own experiences and perspective. All he did he was the same.