"We've lost Europe. Europe now does not have free speech," Kennedy said during a podcast interview with US journalist Tucker Carlson that aired on Monday.
Kennedy also pointed out that US billionaire entrepreneur Elon Musk has been made out to be seen as a "villain" after purchasing Twitter and making it a free speech platform. Musk would have been the hero of the old Democratic party in the United States, Kennedy added.
Earlier, Durov's detention in France was extended until Wednesday.
Durov was detained at the Paris Le Bourget airport on August 24. According to a statement from the Paris prosecutor's office, he is suspected of involvement in a number of offenses, including failure to provide the requested information to the authorities, and management of a messenger that is allegedly used to distribute child pornography and to trade drugs.
According to the French press, Durov, who also has French citizenship, was on the country's wanted list; the businessman could face up to 20 years in prison.