We're not talking about abruptly changing standards, we're talking about holding kids to existing standards for which our society is already calibrated. I don't think your analogy applies (also, are Chinese schools really so much more rigorous than American schools, or is this assumed based on performance of Chinese immigrants?).
Yes, they really are. Look up example questions for the Zhongkao (national high school entrance exam) or Gaokao (national university entrance exam) and ask yourself how North American students at those respective stages would fare.
