Speaking after the Uruguay forward's nine-match and four-month ban was announced on Thursday, Ronaldo said football must be used to benefit the world. (Agencies)
"People have to be held responsible and accountable for what they do in the game," Ronaldo said through a translator.
"Those that do not follow this have to be punished,” he added.
Ronaldo added that he had never bitten an opponent.
"But I know that bites hurt," he said.
"My young kids used to bite me and I used to punish them. In my home, punishment is called 'the dark room with the big bad wolf,' so I suppose for an adult four months with no football is the same,” the Brazilian great added.
The two-time World Cup winner, in 1994 and 2002, praised the overall quality of a tournament he helped organize.
Neymar has been the best player, Lionel Messi will improve and crowd-pleasing Costa Rica “really blew my mind”, Ronaldo said.
He expects the Brazil and Argentina stars to meet in the final on July 13.
"They are both outstanding," Ronaldo said of the two South Americans who have scored four goals each in three group matches.
"Neymar, in my opinion, is the best in the World Cup," he said, citing the 22-year-old Brazil No. 10's increased maturity.
"Messi is a benchmark in football. But I still think he is not very comfortable," Ronaldo said.
"We are still waiting to see the best of Messi,” he added.
Both Brazil and Argentina took until their third match to find their best football so far, he suggested.
"These teams are only going to grow, they will improve," Ronaldo said, noting that “marvelous” Costa Rica might have peaked already.
"I don't believe Costa Rica are going to go very far, but I'm sure they're very pleased with what they have already achieved," he said.
Speaking at a FIFA briefing to promote fan viewing areas in host cities, Ronaldo was engaging and refreshingly direct in his answers.
Could Belgium win it all?
“No. What can I say? We have other teams that are playing better. I believe Belgium may go far but not that far,” he said.
Does Brazil worry over last-16 opponent Chile?
"They are infinitely more concerned than we Brazilians,” he added.
Facing Argentina in the final?
"It's going to be beautiful. If we lose... oh boy. I don't want to think about it,” Ronaldo said.
"Let's hope that Argentina loses first and is knocked out so we don't run the risk," he added.
Speaking after the Uruguay forward's nine-match and four-month ban was announced on Thursday, Ronaldo said football must be used to benefit the world.