I agree that a lot of parents don't teach their children to treat dogs with respect.
I had lakeland terriers, and they seemed to be very attractive to children (possibly because they were quite small and looked like toy dogs). I socialised them both with children from the day they came home from the breeder, so they were absolutely fine with them, but I've had small kids run across a campsite and try and pick them up when they were tethered, crawl under a pub table and poke them, grab their tails from behind and all sorts.
Every time something like that has happened, I've given the child involved an age-appropriate talking to and told them never, ever to touch a dog without asking the owner first. A fair few parents have then had a go at me for telling them off, to which my response was always "Better to be bollocked than bitten".