People who go through police training must do a certain task before the graduate and that task is enduring all of their own defenses, like pepper spray in the eyes and tazering. This is to teach them that these things are very painful, and used in emergencies as last resorts ONLY.
She's 10, I'm sure the kick couldn't have hurt that much. And Really, it seems he tased her because he got frustrated. I think it could have been handled a much better way...
She wouldn't of have gotten tased if the mother didn't say that she could tase her if neccessary