Because evolutionary theory is untrue, unscientific, and false. It is rarely critically and scientifically evaluated by students.
Evolutionary theory is taught in schools as if it were fact. It is not. Many top scientists disagree over it, and all acknowledge it has more holes in it that actual substantive science.
It is actually athiesm in disguise, taught via stealth in the class. It is unscientific, and when subjected to proper scientific scrutiny, is exposed as a falsehood.
Schoolchildren should be encouraged to scientifically analyze and criticise all theories, including evolution. Sadly they are actively discouraged from doing so. I wonder why? Athiests would rather spoonfeed evolutionary theory to young impressionable minds, and resist rigourous questioning.
Thanks for reading. Biblewinsciencefail @ youtube.