I dunno, from what I'm reading the officer in question used excessive force on the girl, but the fact that two individual males were approaching him during a take down (made him out numbered), he probably thought they were coming to assist the girl.
To be honest, there are a lot more guilty people here than just this one officer. The kids were not exactly acting like angels, and the residents seemed to be glad that the police showed up to break up the party.
This seems like an all around bad situation, created by the kids at the pool, then made worse by the police.
Love,
Liz