No, I don't think that's the reason. Nor, come to think of it, do I think it's OK for neighbouring children to screech at 7am and wake their neighbours. Surely nobody thinks that!
But the difference between the noise of children playing out on a summer's afternoon (acceptable if not too loud) and the noise of a neighbour's choice of music (not acceptable if at all audible) is an interesting one nevertheless.
I have given some thought to this, in fact. When I said in the earlier post that the difference may be 'structural', I had something in mind.
As follows. I wonder if you have ever wondered why people, almost universally, enjoy music of one sort or another? Long story short, but perhaps the reason is partly cognitive, in a way. Music, pure music, that is (word-free if you like) has a sort of difficult-to-pin-down (almost?) cognitive structure ... like 'something almost being said', I recall the pianist Simone Dinnerstein putting it a while back. (Others have said similar things.)
And, well, cutting the story short, it does seem that for at least some of us music-lovers, music tends to grab hold of a part of our mind that other noises don't. There's a kind of willy-nilly grab of our cognitive bits involved, if that makes sense.
Now add this willy-nilly grab to the fact that bad art has the tendency to drive out good. And that that bit of my cognitive space that is engaged rehearsing silently - oh, I dunno, the choral finale of Wachet auf ruft uns die Stimme or Goldberg variation 19, whatever (Or just having a rest, perhaps) - gets filled, against my will, by some shit from radio 2 or spotify, what have you. This is about as anoying as it can get. It's torture, in fact. I hate it.
This is probably a bit ott for MN AIBU. But, well, I wanted to make the point that listening to your choice of music may be torture to me in a way that listening to your children's laughter (yes, and even squeals) may not be.
Which, all being said, bolsters my point that, now you know, you should desist from possibly torturing those about you by forcing them to listen to music they didn't choose. ... Otherwise, you label yourself as a particularly selfish and horrible human being. (Which you probably are not, albeit you may have been ignorant of the harm you unwittingly have caused until now.)
Anyway, those who play music in their gardens, please, please stop doing this. Some of us are really quite badly affected by it, to our severe detriment.