I cannot believe people like you still exist....Welcome to the enlightened age. You're only about 200 years late...
"as stupid as being allowed to let a child carry on squawking in a public place without leaving to prevent it from annoying other people."
Sorry. You're in public. No-one is under any obligation to keep you free from annoyance.
Kids squak, rant, tanturm, and carry on all kinds of unholy hell. That's what *you* get for going out in *public*.
Sometimes, parents actually needs to get some shopping done, even if the child believes it must have the red shiny or die screaming about it.
Laws don't exist to make you feel comfortable and free from annoyance.
(There are a whole heck of a lot of names and vulgarities I refrained from using in this post. It required an inordinate amount of restraint. I am almost certain you won't appreciate that.)