Reading this chapter made me think of MOUT (Military operations on urbanized terrain). I thought, deleting the enemy & clearing the room. What a perfect topic to choose, I said. When entering a building you want to delete any bad guys and clear the building for any remaining threat.
This relates to Excel because sometimes you want to remove information from spreadsheets. You can delete cells or cell contents. Another option for removing data is clear, which is found on the home tab which will clear contents but leave the cells and their formatting.
From crayon eating grunts to cubicle hunchback desk-job workers, deleting and clearing anything applies to many aspects of our lives. While I may not be a fan of the second one, I sure do miss the first one... sometimes.