They claim that they are treating everyone the same regardless of ethnicity -- that this agent would have had exactly the same experience if he was some blond-haired blue-eyed Ken doll. Now, I assume you would acknowledge that AA's claim on this issue is either FALSE or it is TRUE. My answer doesn't fit into either or if it does the conclusion you want to draw from it doesn't follow.
The man was treated the same regardless of his ethnicity and he was properly screened from flying on the basis that he couldn't control his temper.