Hi, so it is sexual assault, but it's classed as COCSA ('child on child sexual assault'), and is very much recognised as a 'thing'. There doesn't have to be a sexual motivation for the behaviour to be inappropriate - touching someone in a private place is SA. Likewise, if a child stole a sweet from a shop, they would still be guilty of theft, even if they didn't have the capacity to understand their actions and were not of an age of criminal responsibility. It's important that it's recognised to be assault, so that the victim can receive proper support. SA is traumatic at any age, and the child needs help, not for the incident to be brushed under the rug. My evidence for this? I was assaulted as a child by an older child (of the age of criminal responsibility, but still a child). Since we were children, the incident, which is legally rape, was brushed under the rug at school - it still traumatised me, just as the rape of an adult would.
In regard to making the child out as a predator - where in my original post did I do this? The child is quite clearly not a predator - they are 10 years old. The child needs appropriate help, they need empathy and kindness. The child is not 'bad' or 'evil' - they likely just don't have an understanding of bodily boundaries. They don't deserve to be stigmatised, or told they committed a crime. However, they do need to be told that this behaviour isn't ok, and adults need to be responsible to make sure it doesn't happen again. The child isn't at fault, the adults involved are - however, this doesn't mean that nothing should be done, or that the child shouldn't be taught to respect the boundaries of others.
In regard to suggesting things about the child - yes, I do think it's important to recognise that children who touch others/ignore the body boundaries of others have often been taught to do that. Children model adults: an adult who models respect of other people's bodies teaches a child to do the same. An adult who violates the boundaries of others teaches a child to do that as well. Alternatively, inappropriate touching can be linked to viewing porn at too early an age (which is traumatic for the child and warps their understanding of bodies and sex). This clearly isn't always the case, but should be recognised as something that is actually serious. Ignoring the potential for abuse just because it's unpalatable to consider it/would make trouble is a recipe for disaster.
In short, I made my earlier comment not out of the wish to stigmatise the child who committed the act, but to recognise the experience of the victim. Being touched inappropriately is a humiliating and violating experience. It's important that the victim is actually offered help for what happened, and the only way to ensure that this happened is to label the experience for what it was - assault.