John Cena is not a random American. You and I are closer to random than John Cena, a man who is internationally famous and a professional actor. That’s like saying Tom Cruise is a random American, when you know exactly who I’m talking about without googling.
That said, yes, China censors American media and actors, and it’s horrid. The fact that films get made in America and edited for China and America, is a crime to any artful visions the writers, actors, directors, editors and more may have had. But China itself doesn’t have the time and energy to stop you or I online all the time, it barely can do it within the Great Firewall, due to the sheer scope of the population and area the country covers.