I think one of the things that sets me off about breeders - NOT parents - is their lack of a sense of what's appropriate.
Screaming, hungry baby in post office: appropriate. Mom didn't whip out a boob to feed said baby, and the line was long. None of us wanted to be there. One cannot reason with a hungry infant, or even necessarily quiet it, and perhaps it could not be left with anyone else.
Noisy slightly-more-than-infant in library: inappropriate. Moo was surfing the Web, and from the rock on her hand, not because she can't afford a computer and net access. Take it outside, go home, or make it quiet.
Nursing baby in public under blanket: appropriate. You are protecting me from your bodily fluids and keeping the child quiet.
Nursing sprog openly with big leaky udder in full view: inappropriate. You are exposing me to your bodily fluids, and if I won't swallow/lick someone without a blood test, I certainly don't want your milk anywhere near me.
Children yelling on playground: appropriate. It's a playground.
Sprog screaming in street: inappropriate. Ironically, if I hear enough or a certain type of scream that indicates someone may be hurting said sprog, I will come out of the house with a firearm in oder to defend it. Unless you want to explain this to Sprogly, teach him/her to be more circumspect in the howling department.
But I'm just an evil sproghater...