Mourinho deferred to Holland for post-match media duties after being dismissed from the touchline for berating the officials to a chorus of "Jose Mourinho, he sits where he wants".
The manager took his seat behind the dugout and next to a surprised fan, who took a photo of himself alongside his neighbour and posted it on Twitter.
"His frustration was clear and, in my opinion, totally justified," Holland said.
"Why would it take an hour before finally an issue was addressed? He showed his frustration and then was sent to the stands."
Mourinho and Holland told fourth official Trevor Kettle of their unhappiness with Cardiff's tactics on "countless occasions", without it being acted upon.
Chelsea's equaliser was a result of an error of judgement from referee Anthony Taylor.
David Marshall bounced the ball in front of Samuel Eto'o, who simply stuck out a leg to nick it, even though FIFA rules state the goalkeeper is still in possession at that point.
Eto'o then contrived to miss after receiving a pass from Eden Hazard, who netted while the Cameroon striker was on the floor.
Eto'o did claim his first Chelsea goal midway through the second half and Oscar and Hazard, with his second, wrapped up victory.
Mourinho is now unbeaten in 64 Premier League matches at Stamford Bridge but few can have been as incident packed as Chelsea claimed a fourth home win from four this season to extend their unbeaten home run to 12 matches.
On the controversial equaliser, Holland said: "From my point of view, it looked to me like the goalkeeper was bouncing the ball.
"The referee had a very clear view of it and was happy with it and we move on.
"Over the course of the season, those things go one way or another for you."
Holland praised Chelsea for responding to a defensive lapse which allowed Mutch to put Cardiff in front, when Luiz left the ball for Cech.
"It wasn't a good start for us," the assistant boss said. "The players responded very well from that."
Eto'o scored his first Chelsea goal on his sixth appearance in the second half and Holland hopes for more at Schalke in Tuesday's Champions League Group E clash.
Holland said: "All strikers like to be scoring goals. It's what helps to make them tick and to get off the mark will I'm sure be something he's very, very happy about. Hopefully we get the benefit of it immediately."