Ok found more info
https://www.bloomberg.com/news/articles/2018-08-30/trump-says-mccain-flag-flap-wasn-t-fumble-after-disagreements
McCain lost the 2008 presidential election to Obama, an outcome the senator called a “privilege” in a letter to the country released after his death.
Asked if McCain would have been a better president, Trump declined to say, even as his press secretary, Sarah Huckabee Sanders, stared at him.
“I don’t want to comment on it,” he said. “I have a very strong opinion, all right.”
Sanders, he joked, was “having a nervous breakdown” over his response. “Maybe I’ll give you that answer some day later.”
WTF IS WRONG WITH THE PRESS?? WHAT KIND OF QUESTION IS THAT?