Well his statement is a little polemic isn't it.  Of course he is wrong.  The US does have a culture, in fact many cultures, depending upon where you live and who your family is.  The US differs most significantly from China in that anyone can become a citizen.  Also an important point, Chinese often find it difficult to separate culture from nation.  The US is very dynamic and changing.  Ideas abound.

Hi I from Peru, South America.. and that your teacher is rigth because my country for example has a interesting background.
In Peru we have three region: coast, highland and jungle and each region you can find information about our history. In the middle of the highland and jungle the Peruvian has an important ruin its name is Machu Picchu that was built by the Incas.
Enter machu Picchu in some search engine (google) and maybe you can have a better idea about Machu Picchu.

Bye

At least he himself proved he was right, no?