Rioters promote stereotypes about black people. They only bring negative attention to problems. Even if they did bring attention, it would not be worth the lives of innocent people. Bringing attention to your cause is not more important than peoples lives or businesses. Nothing gives you the right to harm innocent people.
The violence and damage done by riots is not in anyway justified. This type of violent behavior only hurts the cause of people seeking legitimate change. When people see the massive damage done during riots, they often associate the those people rioting with people who are striving for change through peaceful methods.
No, riots do not bring attention to otherwise hidden problems. All a riot does is cause the rioters to appear uncivilized. There are more civilized and less violent ways to bring problems to light. Peaceful protests, boycotts, and other such actions can bring a problem into the public light without causing physical harm to anyone.
Race protesters rioting do not bring attention to otherwise hidden problems. Instead, this violence distracts people from implementing positive solutions to real problems. Many citizens that would otherwise be sympathetic feel resentful when they see violent protesters on television. A better tactic would be to create a positive dialog between government, the police and the community.
The issue with rioting as a protest tactic is that as soon as the first bottle is thrown or window is smashed, the general public turns against whatever group is protesting. So while the media attention is tremendous, it's not like it's shining a light on the injustices of the system. It's mostly showing idiots who the public hates.