What to call strangers kids?

Sarah

Ladies I'm not a parent. I always show children the same respect I show adults but i just got my ass CHEWED at the gas station.

A woman and little boy about 5 or 6 are walking out ahead of me. He stops and holds the door for me and I smile and say "thank you sir!", he smiles back And I keep walking.

Y'all, this woman comes at me screaming not to call her kid sir because he's not grown and I should address him like the child he is and I could've said "hun or sweetie"!

Ummmmmm what?! Y'all if I'm wrong please tell me! What should a stranger address your child as?