It's a rural school district in N.J. Grandson is 11. Daughter gets a call from the guidance counselor that

[cab67]

9. At his age....

....the finer points of argumentation might not have fully developed. But if I was with your grandson (which I'm not), and if it were appropriate for me to give him advice (which it's not), I'd reinforce the lesson that arguments are strongest when one is not including insults against one's opponent.

He was right to argue in favor of his opinion. And the best way to come on top of an argument is to stick to the argument and not get dragged into name-calling.

But as you said, he's 11. My daughter is about the same age (10), and her tolerance for being verbally bullied without retaliation is not as high as mine.

My $0.02.