Kids can do that without mal-aforethought, just 'cos they don't know the dangers.
Don't bees do themselves some serious injury when they sting (and they can only do it once in their lives) because their sting is barbed and comes detached from their little bodies? At least that's what we learnt in biology. So there's some incentive for bees not to sting unless they are really frightened.
Well, I suppose it does hurt as much. Just I'm not fundamentally so scared of a little sting as I don't get much reaction from it. But being little makes it way more scary.
Hmm. We'll have to disagree there, they scared the cr*p out of me when they chased me from a rubbish bin in the New Forest one summer when I was < 10.
To me, and you'll hate me for this, wasps=pointless and nasty, splat 'em. Hornets=pointless and even nastier, splat 'em. Bees=honey=nice and not at all pointless so I'm more forgiving of them, and I don't believe them to be as fundamentally evil as wasps anyway.
As for trees, I plant them from time to time and I'll chop them down if I have reason. I don't worry too much about it - I think I've planted more than I've killed so the trees aren't doing too badly ;->
Tim