Why do a lot of young Thug males where two layers of clothes?

Because they're often involved in illegal activites and so they can run from the police and change clothes so their description (clothing) changes. 'He was wearing grey pants and a white shirt.' Suspect in area that matches general description is now
wearing red shorts and a black 'wife beater' t-shirt. 'Naw, dat wuszn't me who robbed dat licker sto'.'