How is that thug? To me, "thug" is an attitude and one's actions, rather than appearance. If the braids are the only thing about him that might identify him as a thug - if his shirts are tucked in and his pants are not at his knees and he doesn't have gold teeth and a massive rope chain - then someone is racially profiling.
To me, a white guy shaving his head to the scalp could be equally and erroneously reflective of his beliefs - shaved heads automatically mean skinheads, right? That is about as plausible as a black guy with braids being automatically called a thug.