The 65-year-old believes that the Portuguese forward has no grounds for complaint due to his model lifestyle, and also gave his views on the problems facing Fabregas and Vilanova
The 27-year-old sad that he did not celebrate his double strike against Granada on Sunday because he was "sad" with a "professional" issue, within the club.
But Rexach, who has coached Barca's youth team and 'B' team as well as guiding the senior squad in caretaker and full-time capacities, was unsympathetic about the recent plight of Madrid's prized asset.
"If Cristiano is sad, people should go into the streets and cry," the Catalan sarcastically remarked.
"Ronaldo can't ask for more from life. He's a top player, he has everything.
"He is physically fit, well-built, has money, success, is one of the best players in the world.
"I don't know what else he wants, so for him to be sad is sacrilege."
Rexach also discussed Cesc Fabregas' slow start to the season, and urged fans and pundits to have patience with the former Arsenal man.
"Cesc has to find his place within the team," he continued.
"When he first arrived he had a great start, scoring goals, but now that Messi is playing a bit deeper he cannot find his ideal position on the field.
"People must have patience."
Considering the task ahead of Tito Vilanova, Rexach offered his advice: "I believe that better than improving, what he has to do is change things up, to vary things a bit, because everybody already knows how Barcelona play, the people know that Messi plays a little deeper."