Its modern dont give a fuckery tbh. Come on, we all know how difficult it is to get little baby off to sleep in hot summers. It can be a nightmare sometimes. I bet there are times you would pay £1m just to have the peace and quiet of a full nights sleep given the chance.
Of course your child and his friends have every right to be out on a warm summers evening/night. Of course they should be able to laugh and chat and not give a hoot about others peace. But we live in society that needs a bit of give and take to run along. We also get back what we give sometimes.
I have long since done my stint with babies but i do remember the battles with warms nights and sleeping. Our direct neighbours recently had a baby and over the road did too. Have we changed our lifestyle for them? Not at all, just a few simple adjustments they didnt even ask for.
My son has a loud car (Its actually computer controlled so he can tell it to be quieter). I asked him to ensure its always on the quiet setting when coming and going. Also to reduce his music volume when coming onto our street. Little things that i know would annoy the neighbours with newborns.
We also get to about 9pm and make sure volume levels are discreet outside. We love sitting on an evening in the back garden but it doesnt take a rocket scientist to know it might cause them issues. We just lower the volume of our chat. Its not difficult.
The actions you take might not make a jot of difference and you can quite rightly refuse. But its a reflection of yourself and how you treat others and may just reflect how they will treat you in future.