Moratti was in the stands cheering on his side's first Serie A home win since January.
Preziosi rapped: "It's never a pleasure to lose, but it's not easy to score four goals at San Siro either. I don't understand what Moratti had to celebrate, seeing as Inter let in four at home. We don't even score four against the little teams!
"Genoa put Inter under pressure after the break and in my view the Nerazzurri played a terrible game.
"We handed the first half to Inter and played in a very sluggish manner, just as they wanted us to. It was obvious that if we don't raise the tempo, then we cannot compete with the Nerazzurri players.
"We had a problem in midfield, where some players focused only on doing fancy tricks and managed to lose the ball in dangerous situations," said Preziosi, referring to Miguel Veloso. "It went better in the second half, when we removed Veloso.
"He is a great player, but he has to understand in Italy you need to be much quicker. If he doesn't understand that, then he'd best go play in another country."