That is not correct. Americans know exactly why and how the 4th of July is celebrated. However, Americans are getting fewer and fewer as each year passes. The people who now live here may not know, but they are not necessarily Americans. Merely living in the United States does not make one an American. Being an American is a state of mind.
The above is my opinion and my opinion only. Others may differ.
as was stated in the source comments...they are from California.