I don't know what this means?
My guess is that the snappy comebacks that sound so good to us rarely have the intended effect, especially the ones that impeach the listener. And honestly, I personally don't believe that's usually the underlying stimulus behind this sort of scenario. I think it's more to do with people fearing what they don't understand, and using derision as a coping mechanism when they encounter what they perceive as aberrant behavior. It's easier than trying to understand.
If it's okay with you, I would substitute the word "courage" for "balls", but yeah, you're absolutely right. People have made such comments to me numerous times, and surprisingly, more often than not it comes from a gracious, sweet spirited young person. Which always lifts my spirits and gives me hope.