Most of you are well aware that there is a history of mistreatment from cops toward blacks, spanning many decades. This history stemmed from the malicious treatments blacks first received by being enslaved, only to be released in a nation with Jim Crow laws. One of the most serious consequences of this, historically, was racist people who were police officers, abusing their power to abuse blacks.
After many decades of this type of abuse, including being hosed just for marching peacefully, race relations between blacks and whites very, very gradually started to improve. However, a side-effect of the horrendous mistreatment and decades of denial of equal rights to blacks, resulted in a generation of blacks that resorted to crime, as many systemically impoverished people around the world do.
Stay with me.
Over time, the criminal mindset started become an acceptable way of life. This crime culture, heavily bolstered by the hip-hop culture, gave blacks (especially black youth) something that they very easily and readily identified with.
More time passes. The "thug life" culture gets not only more popular and romanticized, but even fashionable. At the same time that this is happening, race relations still continues to improve. Racist cops still exist, however. Infamous examples include people like Mark Fuhrman ( a racist detective who used to wear blackface). This is where things get complicated.
There are many Mark Fuhrmans still mixed in with the decent cop who simply want to do their jobs. At the same time, blacks, due to the harsh systemic mistreatment toward them, have high rates of crime. As a result, the line between racism from cops, and decent officers doing their jobs (like cops who use force justly) starts to seem blurred. Instances of racism are unclear. Are cops just racist, or are blacks simply criminals? Unfortunately, a little of both is true.
More time passes. Race relations improve further. We have a black president. Neil Degrasse Tyson is the most popular scientist among the general public. Oprah is the arguably the most popular talk show host of all time, at least among among women. Jay Z (a black rapper) has as many number one singles as the Beatles, his black wife, Beyonce, is frequently hailed by popular U.S. magazines like People, as the most "beautiful woman in the world". The best athletes are black (Jordan, Ali, Michael Johnson, etc.). At the same time, a culture of crime, because of the aforementioned reasons, persists in black culture. This causes an understandable disdain from those who feel blacks are making excuses, given how successful and intelligent blacks have proven they can be.
So...we are now at a point where, where we can legitimately argue that blacks are causing most of their own problems. However, racism still isn't dead (the KKK still exists, Donald Sterling, etc). As a result, whenever cop does something that's even possibly, because of the long and terrible history evil toward blacks, especially from cops, there's understandably a very strong reaction from the public against the cop, often resulting in rushes to judgement, and automatically deeming any cop even accused of wrong as guilty.
Baltimore: wounds from cases like Treyvon Martin (a youth minding his own business, who was followed by and then killed by a *white* man, and wasn't even charged until the public protested, and was still acquitted). Not long after, cases like Eric Garner (a man who was choked to death with a banned hold, even though he showed zero signs of violence, even though he clearly told the cops that he couldn't breathe, which resulted in the officer being acquitted, despite the videotaped evidence). Many still believe that Michael Brown's killer was unjustly acquitted.
Keeping in mind how soon each of these cases happened after each, merely months (sometimes only weeks) apart, blacks feel like they're getting slapped in the face.
Baltimore probably wouldn't be happening right now if not for cases like Eric Garner, Martin, and Michael Slager (who shot a fleeing black man named Walter Scott in the back). Maybe some protests, but I doubt emotions would be this high if not the seemingly endless succession of *possible* brutality cases. Some are cases of cops overstepping their authority (Garner) and some may or may not be, like Michael Brown. The problem, is that because of the history toward blacks, the line between who's doing their job correctly and who's not, seems blurred. Through the lens of a people that has experienced oppression, their vision of what's actually happening may be tainted.
So that's where we are now.