If you ask men and women whether sexual harassment and assault are major problems you will get a widely differing answer. Who's right? More than likely the group who is the object of the abuse.
Similarly on police accountability, the answer from whites and minority/poor communities will be very different. Who's right? Well, again, more than likely the group who is the object of the abuse. No offense to white people, but many of us do not live in or near these communities and really have no idea what it is like.
The protests in Ferguson, which have spread to many parts of the country, are not about this isolated incident, they are about lingering and widespread patterns of abuse. That doesn't mean all police are bad, or that all departments are bad. Hardly, but it doesn't necessarily take much for it to be a problem.
In the case of Ferguson there seems to be some clear problems. The department and politicians are strongly unrepresentative of the communities they serve, and it would not be surprising if the vast majority of the police officers do not actually live in the communities where they work. The cities second largest funding stream comes from the court system: $2.6 million in 2013 from a city of just over 20,000 people. That amounts to an average of $321 in fines per household, and this is not a high crime city. It is fairly average. Something is wrong there. http://www.latimes.com/business/hiltzik/la-fi-mh-t...
I think the fact that they showed up to a protest with full riot gear and tanks proves the point. That isn't the actions of people who care about a community. That is the action of people who are afraid of a community.