“decided that Trump’s tweet must mean that he made tapes of the conversations.” Nobody confirmed nor denied this. They pointed out the Trump pointed out there may be tapes. That’s all you need to report on.
There was no need to decide anything. There was no speculation. There was someone that intentionally gave out false information to the public and press in order to influence the way an investigation was being ran. Trump did not do this based on empirical data. He didn’t do this cause science dictates it. He was not required to nor forced to do so. He produced intentionally misleading information in regards to a federal investigation of which he is a primary part of to help himself in the matter.