YANBU and YABU at the same time. Like others have said, you got annoyed with this girl strangling your DS (valid) but you expect the parents to be stood there watching when they were probably running around sorting the party out.
Then you think other children are 'wimps' for crying when your DS is throwing stuff at them. Ok its cushions and I do hate it when you get the crybabies who do cry over nothing and the parents rush over as if their leg has been hacked off, but your DS is still throwing stuff around.
I am not keen on other children. I totally get where you are coming from. A friend of mine has a habit of telling my DS off everytime we go to playgroup now, when her DS is the slight crybaby as no one can go near him without her hovering over. I heard her telling my DS off recently because my DS and hers were wrestling in a tent. My DS doesn't wrestle but she admitted her DP does is with their DS but mine was obviously in the wrong and not hers.
Last week they were playing together and she was really chatty with me. Then my DS was 'strangling' (he was actually trying to give her DS a cuddle) her DS, I could hear her telling my DS off again, then she refused to let her DS play behind the curtain where my DS was and she was off with me after that.
Yes my DS does run around at group. Thats what it is there for. He can be 'funny' towards younger children (not friends DS, he is only 2.5 months younger, and I really don't know why he is like it) and I do watch him all the time to keep an eye, but I also get fed up when this woman intervenes and tells DS off for no reason, which seems to be coming a habit with her.
Sorry, went off your point there OP. Yes, other children, and their parents can be very annoying. I have no doubt though that others are thinking it about my DS, which breaks my heart really as he is a lovely boy and when we are at home on our own, sits and plays quietly and just gets on with it. He is like a different child when others are around though.