How did Howard treat Willy during their meeting? Why did Willy tell him: “You can’t eat the orange and throw the peel away- a man is not a piece of fruit!”?

Howard is frank and dismissive to Willy. This is Willy's articulation of Linda's "attention must be paid" speech. But Willy's appeal is not for some abstraction of attention or dignity. He is arguing directly to his employer that there must be responsibility taken for employees. Willy gave his youth to the company, and now the company must take care of him.