Kelly visited Ukraine recently and posted what he saw. Musk called him a traitor. Kelly snapped back saying maybe Musk should rethink what it means to be an American, and then debunked a bunch of lies by Trump and Musk about Ukraine and detailed how Trumps' actions are causing the deaths of ukrainians.
He also pointed out that Trumps' comment 'Russia is hitting them hard" sounds suspiciously like POTUS cheering for Russia.