After years of working with kids I heard kids say things like that many times. Or they would say things like I want to kill them or I hate myself, etc. Granted, sometimes they were concerning statements, depending on knowing the kids, their mental status, etc. But often, especially with the younger ones, they just didn't have the right words to express themselves. We would have to explain "I understand that you are upset with yourself, but if you are saying you want to hurt yourself and/or others, then I will have to get you some help. DO you really mean that or are you just really angry and don't know what else to say?"
Usually that is the case and you can just help give them some better expressive words to use.
Hope that helps!
