Black people usually do get stopped unfairly because most of the time when they are stopped, the cop has an idea in his head that this guy is a bad man and should be treated as such based on nothing more than the fact that he is black. There is no innocence until proven guilty when you're black. It usually ends up that you're guilty until proven innocent.
Mr. Thomas's behavior is what got him arrested. He was angry, indignant, cursing the officer, throwing his backpack on the hood of the car, very agitated, pulling away from the officer, telling him he couldn't put hands on him, etc. It was Thomas's vehement behavior that got him arrested.
If he would have said politely, "I am sorry, sir. I was walking around the construction. Can you tell me where I should be walking?"...this whole thing would have turned out different. Fortunately this officer controlled his own behavior well, and was very professional. Refusing to be polite and cooperative and respectful, or worse, trying to run, refusing police commands, getting angry and fighting will get you into trouble EVERY TIME. Follow the commands of police....be polite and respectful.
Unfortunately many police officers have a poor impression of black people and are far more suspicious of them than they are of white people. This leads them to be more likely to stop black people and accuse them of crimes, and to treat them disrespectfully as they tend to assume they are guilty without any evidence.
Black people do not get stopped unfairly. Across the country, many young people of all races get questioned by police. Sometimes, they are not guilty of anything, but might look suspicious. Police do not have a hidden agenda against black people. The news media likes to cover this story because it gets a lot of attention.