Because they harbour bastard bastard insects 
Went to make gravy and my flour is full of bugs. Back up flour (same cupboard) also fricking crawling.
So one dry roast dinner later I'm stuck with the dilemma of what to do.
That cupboard holds all my baking stuff and pasta, rice, couscous etc etc and bugs give me the jitters.
So AIBU to do what I really want to do and burn the bastards?