The contentious moment came with the hosts 2-0 up but under intense pressure.
But Keane pointedly referred back to a decision Styles made at Anfield back in August when he awarded a debatable penalty in Chelsea's favour.
After that incident the official apologised to Liverpool but was demoted as punishment.
"Carragher lifted his hand above his head and we have been told last week when we had Howard Webb (another Premier League referee) at our training ground that such an incident would be a penalty.
"Rob gave a penalty against us at Blackburn this season against Danny Higginbotham when he did just the same thing. As I said, we were never going to get a penalty here."
After the match thousands of fans on the Kop and in the main stand stayed behind to protest against the club's owners Tom Hicks and George Gillett.
The Americans have secured a refinancing package for their purchase of the club 12 months ago and have seen off a potential takeover bid from Dubai International Capital.
Benitez, though, was only concerned with his side's victory.
He said: "It was important to score the first goal, important to win and important to find our confidence.
"The fans were very patient. It was a frustrating first half but they stayed with us and in the end we gave them something to be happy about because they have not been getting the performances they deserve of late."