This statement is presented in the article as one of O’Reilly’s lies:

In a 2004 column about US soldiers fighting in Iraq, O’Reilly noted, “Having survived a combat situation in Argentina during the Falklands war, I know that life-and-death decisions are made in a flash.”

He said he was in Argentina. The Falklands are not in Argentina. How does his sentence qualify as a lie? You could take it as false if you decided to deem las Islas Malvinas as part of Argentina, and then deemed him to have said that he was there, but this is not the only possible way to parse the sentence.