You seem to misunderstand the race issue here, because the incident you brought up was so completely unrelated, but yes, if some people were decapitated in a horrific way, and the police said "well, when we investigated, there was this guy walking around in the street with a bloody hatchet, but we let him go because we have a law that prohibits us from investigating people who carry hatchets." Then yes, people would be screaming at the police force for completely fucking up, and people would also be saying that there shouldn't be a stupid law that exonerates anyone carrying a hatchet.
However, in order to extend the racial aspect to it, we'd have to be living in a country where white people are a minority... but since we've already entered the Twilight Zone here, can we just get back to actually talking about what happened, instead of speculating on how people might have reacted to a completely different case which could have ended differently than it did?