There is always controversy at every Olympics, we just forget about them.
In 2008, the last Olympics in China there were many controversies which included;
Controversy about China's record of human rights, with calls for boycotts
the levels of air pollution due both to concerns about athletes' health and concerns that Beijing had failed to live up to promises it made during its Olympic bid.
The gymnastics competition caused a major worldwide controversy during and after the games when some Chinese gymnasts were accused of being under the minimum age, but then cleared after an investigation.
ticketing problems
Security problems due to civil unrest in Tibet and terrorist attacks by Xinjiang separatists.
displacement of Beijing residents due to construction and demolitions.
Then the 2004 Olympics in Athens was exactly the same;
Approximately 70,000 police officers patrolled Athens and the Olympic venues during the Olympics. NATO and the European Union also provided minor support, after Athens asked for co-operation.
Greek authorities announced that a roof it had initially proposed as an optional, non-vital addition to the Aquatics Center would no longer be built.
From fencing to swimming to equestrian to gymnastics, hands have been wringing and protests flying over judges and scoring. The cacophony culminated in a surreal scene as U.S. gymnast Paul Hamm, already caught in the eye of a storm over his all-around gold medal, had to wait nearly 10 minutes to begin his high bar routine while fans lustily booed the score given to the previous competitor, Russian Alexei Nemov.
While Hamm waited, the overall score changed before everyone's eyes, to 9.762 from 9.725 (out of a perfect 10), after two judges, one from Malaysia and the other from Canada, raised their marks. Nemov finished in fifth place but afterward said he "would like to thank all these people for what they did."
the IOC's decision to give the Canadians duplicate gold medals after a French judge said she had been "pressured" to score a Russian pair higher. "It was a case of clear corruption and manipulation,
Russia complained about the scoring that cost gymnast Svetlana Khorkina a gold medal in the women's all-around competition and kept Alexei Nemov off the medal stand in the high bar finals. Fans protested Nemov's high bar score, and judges relented and boosted Nemov's score. He still finished fifth.
American swimmer Aaron Peirsol was disqualified after winning the 200 backstroke. The decision was overturned 30 minutes later. The mix-up was because of a blank judges' report.
Hungarian fencing referee Joszef Hidasi was expelled from the Games and suspended for two years after making errors during the gold medal match in men's team foil. Hidasi made mistakes in six scoring decisions — all favoring gold medalist Italy, which beat China.
Germany lost its gold medal in the three-day equestrian team event after protests by France, Britain and the USA.