Sure, ideally bystanders and local businesses (in particular) would be spared. But nothing about the historical events leading to now is ideal.
And if your expression of pain includes looting booze from a liquor store or a TV from Target, what exactly are you trying to say? By the way, those bystanders and local businesses owners are people of color too.
That shooting wasn't part of a system of institutional and deep rooted racism. Neither was it part of a system where white cops routinely harass black people with no basis other than the colour of their skin; where white cops use horrifyingly excessive violence and all too often murder black suspects, bystanders and innocents - a system where the perpetrators of that violence and murder are almost guaranteed to face no repercusions at all. A system of ingrained inquality that spans decades.
Black people are harassed, racially abused, set upon and shot frequently by white cops in the USA - and the videos we see pretty much on a daily basis in the news and on twitter are only the tip of the iceberg.
As someone in the UK, the the inequality and racism that still exists in the USA, "land of the free", is mind boggling, sickening even. Something has to change, so yes, I can fully understand protests and rioting.