Roura, who is in charge of the Catalan giants while Vilanova recovers from a cancer relapse, has been criticised following Barca's drop in form since the turn of the year.
"If we win, everyone is quiet and Jordi is the best," Alves told Barca TV. "But when we lose, people have to have someone to aim their anger at.
"We don't listen to any of that. Everyone knows how important Tito is for us, but when the boss is not here that's when we see how good the team really is.
"Criticism is part of sport, that's what's wonderful about it."
Barcelona currently top the La Liga table by 14 points.