Well let's balance this out a bit (as a parent with severe autism who hits out)
The parent of the victim only really heard their child's version of events, the school doesn't go into details really. The parents don't know what's going on, what's being done to help. All they know is that their child is suffering. This is worsened when the bully has SN. The parents feel bad for the bully having SN, know the child can't help it but they also don't want their child hurt, so they have no one to be angry at, don't know what's being done to stop it, and probably feel just as helpless as the victim.
Ok now for the parents of the bully (SN or emotionally scarred children)
They know all the details of what is going on, have meetings, think of strategies, try hard to stop it, they do have some power.
However, they also have massive worries, are all the parents judging them? Will their child grow out of it or end up in care being restrained because of violence. Why are none of the strategies working? Is it something they've done? What about the poor child being hurt? Are they ok? Is my child's SN impacting so much on other children emotionally that they will end up with special needs too? Will my child be excluded? Need a special school?
It's a horrible situation for both sets of parents. Horrible. I wouldn't wish either on anyone
BUT and here's the biggy... Some children's parents don't care. Their kid isn't unhappy and the other kid should just stop being so weak. If that's the parents attitude then yes, they do have it easier.
It's pretty easy to tell the difference between these parents, go and talk to them in the playground. Not to attack them but just talk to them.
The parents at DSs mainstream school were never angry at me, or DS, they were angry at the school after I told them they weren't putting in place the recommended strategies so this is why things were never getting better. They complained a lot, not about DS (although the head teacher tried to make me believe this but every parent who complained came to me first and had my full support and I told them the type of things they could say in the hope that DS would get the support on the back of other parental complaints) but about the lack of action by the school.
So, to sum it up, it all depends on whether or not the parent of the bully cares. If they care, it's just as hard. If they don't it's easy for them to bury their head in the sand as their kids aren't being hurt. 