He lied. He didn't tell a little fib; he ducked the truth in a very insulting way.
On Tuesday night, her lawyer, Mathew D. Staver, said in a telephone interview that Ms. Davis and her husband, Joe, were sneaked into the Vatican Embassy by car on Thursday afternoon. Francis gave her rosaries and told her to “stay strong,” the lawyer said. The couple met for about 15 minutes with the pope, who was accompanied by security guards, aides and photographers. Mr. Staver said he expected to receive photographs of the meeting from the Vatican soon. ...NYT
This may not have been the pope's personal decision; it may have been a Vatican ploy. What's wrong is not the visit with Kim Davis, a minor Kentucky bigot. What's wrong is that it was hidden and he effectively lied about it, playing both ends against the middle, ducking responsibility.