After all, Americans have a negative reaction when people from abroad make fun of our peculiar habits.
And painting a whole nation, undoubtedly your largest customer base by far, with the actions of a few folks in China is gracious?
It's not good business to alienate your base customers.
No, but people do it: whether it's Chinese who see some boorish Americans in Beijing or Americans who react similarly to foreign criticism of the US.
I'm not suggesting the bimbette who gave the speech didn't have a bad case of the "ugly Americans" -- only that there really are Americans who behave boorishly abroad and it's not a bad think to remind graduates that it reflects ill on the whole country.