will stack , 22 , posted honest video on facebook ; it has since gone viral .
in footage , he disputes claims all white officers racially profile suspects .
he recounts his own experience with ` caucasian ' cop in south carolina .
says he was given warning and went on his way after listening to officer .
` not all officers are crooked ... racist , bad people , ' he says in the footage .
mr stack is a former college student and u.s. army national guardsman .
has been widely praised for video , which has received 1.7 million views .