"I made a terrible, terrible mistake," he said. "I was ill. I didn't understand. . . . I was a special education student myself. I know what it is like to feel that way."

So this is what Mr Chinn says in response to his really really bad remarks.
How was he ill? Is stupidity and bad taste an illness?

He didn't understand, really? He says he was a special ed student himself, I seriously doubt, if he was, that he didn't "understand".

He knows what it is like to feel that way? Really? Then he is without excuse. He is either a liar, or he means what he says and is therefore a hypocrite. In either case he isn't ill.

He is right, he made a terrible mistake.