However, another interpretation of the purpose of schooling might be
considered. It is, in fact, the purpose of public school to educate
children to be able to function successfully in the society in which they
are raised. Children are taught history so that they can understand why
society works the way it does. They are taught science and mathematics so
that they can understand why the world (and business, where they have to
earn a living) works the way it does. They are taught language and
literature so that they can share a common understanding of ideas, in order
that they can communicate effectively. This is, in fact, one of the most
compelling arguments agains bilingual education in the United States. The
language of the US is American English (I know some folk from the UK will
read this so I won't presume...). If you want to be successful in this
country (by and large) you better know English.
That being said, the argument can be made that evolution should be taught
because if a student has any interest in biology, he better understand that
the great majority of biologists believe that evolution, common descent,
and some flavor of Darwinism is the explanation of the diversity of life on
earth. If you want to communicate effectively with them, you need to know
that this is how they think.
Of course one of the problems with public education in America is that not
enough time is spent on critical thinking, because it is difficult to
teach. In a properly functioning educational system, students would also
be taught that just because a majority of the people think something is
true doesn't make it so. So it is perfectly possible to teach that
biologists believe in evolution while allowing that a student doesn't
necessarily have to believe it herself.
This argument cuts both ways, by the way. I happen to think it is a crime
that the Bible is not taught in public schools. Such a huge chunk of our
common expression, ideas, and literary allusions come out of the Bible, not
studying it in school is inflicting on students an incomplete education.
Just as the YECs don't like to hear about evolution, the humanists don't
want to hear about the Bible. They're both wrong.