I suspect that the police are hesitant to attach "hate" to the crime because it has not been proven that the assailants knew that Christopher was actually gay. However, whether or not the assaulted person is gay is almost beside the point. Assaulting someone because one believes that the person is gay (or Jewish, or Muslim, etc.) is key to establishing a hate crime. In fairness, this could simply, and horribly, be a case of random violence; that Christopher happened to be the dreadfully unfortunate person whose path crossed with a group intent on violence. Perhaps, although it's much more likely that the thugs in their SUV fortress, pumped up on whatever and with bravado fuelling a dangerous machismo, spotted Mr. Skinner on his way home and marked him as a fag worth bashing.
With deepest condolences to the family and friends of Christopher Skinner. May he rest in peace.