You are a sympathetic Cylon
A revealed Cylon player must always pass the You are a Sympathizer and You are a Sympathetic Cylon cards to another player. The Pegasus rule you quoted is for "when a human player receives" the card. See page 7 of the Pegasus rulebook:


  Sleeper Phase: When a Cylon player receives Loyalty Cards during
  the Sleeper Agent phase, he looks at all of his facedown Loyalty
  Cards and gives them to one human  player of his choice. If the Cylon
  player receives a “You Are Sympathizer” or a “You Are a Sympathetic
  Cylon” card, he does not reveal it.  Instead, the human player he
  passes it to must immediately  reveal this Loyalty Card as if it had
  been dealt to him.


So the original rule in the base game hasn't changed. It's just been expanded to include the You are a Sympathetic Cylon card.