Nothing.

You had the bad luck to encounter an agent with a chip on his shoulder.

You had the good luck to have declared allowed foods when you encountered this jerk. Imagine if you had not declared these perfectly acceptable foods and he had decided to go after you because you 'failed to declare'.

Not all agents are like this, but you have probably noticed how many people post that the best thing about GE (besides time-saving) is reducing face-time with bad-tempered agents.

FWIW, I have declared food and had an agent ask me, with a raised voice, why I was 'wasting' his time declaring cookies and chocolates. I could only apologize; it was not the time to point out to him that I was following the rules of his agency.