Would I be an asshole if I told people to stop saying this to my son ?

My son is almost 6. He's much shorter than most 6 year olds , he's very low on the height and weight chart but he's within healthy limits and it's just genetics that she's a small kid. My husband is short and so am I. My son eats well and has no health issues.

Everywhere we go adults make comments to him about his height and weight "omg I thought you were 3! " "He's so tiny like a baby !" "What a cute little guy " "wow my son is the same age and he's so much bigger" "does mommy feed you" ..and I could go on. It's all the time it's so incredibly annoying because it makes my son insecure. This is adults, not kids saying all these things.

At the doctor just now a nurse said to him omg you are so tiny ! My son looked embarrassed. I am boiling and considering tell her that that's completely uncalled for.

Am I over reacting or is it completely unnecessary for adults to comment on a kids height and weight like this ? Would I be an ass if I told them that