Because if they were open and honest,
the teachers who recommend texts would
not recommend them; the principals and
school superintendants who order them
would not order them and, consequently,
the publishers would not be able to sell
them - all because they would not promote
what has become the established party line
on the CW and all things having to do with
the CW. Open and honest is not what sells.
Imagine what would happen if the truth about
all Lincoln's unconstitutional shenanigans
were to appear in a HS text book today and
high school graduates were to graduate
believing Lincoln as being "traitorous"
instead of "great."