The 30-year-old picked up his first caution for dissent early on in the contest - which was ultimately settled by Cristiano Ronaldo's 85th minute strike - before bringing down Luis Suarez with a mistimed lunge.
Ramos was fortunate the referee was in a leniant mood after a string of poorly executed tackles, and the former Real and Barca star was less than impressed with the defender's behaviour throughout the tie.
"[Real] deserved the win today," Laudrup told Sky Sports. "The second half they were the better team. Even going down 1-0, coming back and scoring the equaliser.
"And down to 10 men, a stupid second yellow card from Ramos. I really think they deserved it. And apart from that, they had two or three good chances."
"He [Ramos] did it when he was 20. Then, okay, you can say he's inexperienced. Now he's 30 and he's still doing it. He could've had four yellow cards!
"The first one after 10 minutes, he could've been in the dressing room after 17 minutes and he's one of the most experienced players and one of the best defenders in the world. But you cannot do that."
Real's win sees them close the gap to the league leaders to seven points but Zinedine Zidane's men remain in second spot in La Liga.