For some of us who care passionately about learning and opportunity for all (and who don't see education as a race to the top for a few) so much of current policy and practice IS a crime scene.
The extremity of the metaphor matches the strength of feeling when it comes to the crimes of deskilling teachers and depriving children of their birthright as learners.
Want a more "cheerful" metaphor about the "crime" of grading?
Grades are the candy floss of education. Appealing to some in the short term, nutritionally worthless and ultimately destructive.
Like a cheap tin trophy.
The cattle prod for the bully, the carrot for the desperate and a prop for the incompetent.
A diversion tactic, sidelining learners from what actually matters.
The candle snuffer of the love of learning.