Kalulu was sent off after Inter's Alessandro Bastoni tumbled to the ground and immediately gestured towards the referee demanding a card, indicating that Kalulu had grabbed his shirt to bring him down. Television footage suggested there was no contact between the players.
Juventus, down to 10 men after the sending-off, lost 3-2, meaning Inter are now eight points clear at the top of the league.
"We are very sorry about the incident, about La Penna's decision, which was clearly wrong, and about the fact that VAR could not be used to rectify it," Rocchi told Italian news agency ANSA.
"La Penna is mortified and we are close to him, but I have to tell you the truth that he is not the only one who made a mistake, because yesterday there was clear simulation."
Kalulu made the VAR gesture as he protested his marching orders, but the league's protocol prevents the use of VAR in yellow card situations, including for second yellows that lead to sendings-off.
Juventus coach Luciano Spalletti and director Giorgio Chiellini later confronted La Penna in the tunnel.
"Something completely unacceptable happened today, it doesn’t matter whether it happens to us or someone else, and from tomorrow presumably VAR will have to change, because this is not acceptable that so many errors keep happening even in big games like this," Chiellini told Sky Italia.