You obviously haven't spent much time in America, as Americans are the first to criticize and make fun of the failings of their own country.
The concept of "face" is a big difference between American and China.
A world leader could call Trump an idiot, and most Americans would nod and go "You're just figuring that out NOW?"
A world leader could call Xi an idiot, and the Chinese press would be calling for an official apology and encouraging citizens to protest said country.
If you can't laugh at yourself (or criticize yourself), you're never going to be viewed as "cool." You're only going to be seen as "thin-skinned."
That's not true at all. Libel and/or slander has very real consequences.
I take it you've never been in line at a Chinese bakery? That'll make a Rugby scrum look polite.
What you are claiming is completely and utterly false.
Offensive speech is protected under freedom of speech. What's not protected are your feelings if you are being offensive.
The remedy to offensive speech is better speech, which is why nasty people like the Westboro Baptist Church can exist, but they can't demonstrate anywhere without counter protestors appearing.
Basically, if you want to say something rude and offensive, you can, but you shouldn't be surprised when you get called out for being a jerk.
Freedom of speech is a fundamental aspect of American democracy and the only people who want to curtail it are right-wing fundamentalists because they are afraid of thoughts and ideals.