Because this is totally normal.
President Trump issued a veiled threat to fired FBI Director James Comey via Twitter today:
"James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press!"
UPDATE - via CNN:
Former FBI Director James Comey is "not worried about any tapes" of conversations between him and President Donald Trump, a source familiar with the matter told CNN Friday, adding that "if there is a tape, there's nothing he is worried about" that could be on it.
And then there's this from NBC reporter Ken Dilanian:
A source close to Comey told me this morning: “He hopes there are tapes. That would be perfect.”— Ken Dilanian (@KenDilanianNBC) May 12, 2017