They probably do not understand the import of their actions but they will almost inevitable grow up to be the same sort of people that they are as kids that burn other kids. They will not be permanently sequestered “because of their youth” but they will become incarcerated adults or die on the street.
Perhaps I just want to believe that it was an accident. The thought that these evil kinds of children are being produced is just too bitter of a pill to swallow. Now the fact that they were even setting the shack on fire is cause for concern. But attempted murder on another human is quite different. They all certainly need to be evaluated to see if they can determine that, if possible.