It's been suggested Guardiola can't win in Europe without his former Barcelona star Leo Messi.
But Setien says: "He's a reference, and it saddens me to get involved with Guardiola, who is a reference for thousands of coaches.
"People who rejoice in the failures of others seems an aberration, but we already know what sells..."
He added: "He is a great player, it was an option that we had and I think it is good that we did it.
"He has done a good overall season, he is young and he has a projection and the club is good at betting on him."