Just because you took high school Biology or Physics did not make you into a Biologist or a Physicist. It merely introduced you to the most distilled and complete parts of those fields and had no pretense of professional training or a career choice.
In a similar manner, people are pushing for the most distilled parts of Computer Science to enter school curricula. This would _not_ mean that after that course you are a programmer, or a computer scientist, or even proficient with computers.
People fail at Biology or Mathematics and have different aptitudes.
What it would mean, however, is that you are exposed to _computational thinking_ [http://www.cs.cmu.edu/~CompThink/], an understanding perhaps that somethings are computable and somethings are not, rudimentary programming skills, and a different outlook on Computers in general.
Thus, people would no longer look at computers as purely black boxes and magical, they would understand them a bit better and have a rudimentary understanding of a field which affects almost everything in their life today.
We feel Physics and Biology and Chemistry and Calculus are important, why not add Computer Science to the mix?
Do not confuse professional training with simple education.