End the racial and demeaning treatment by Police in Bend, Oregon

Recently my son, (whom is blessed to be of all racial ethnicity, African-American, Mexican, as well as Caucasian), was stopped by a Police Officer in a vehicle occupied by four other Caucasian young people. The oldest, a male whom is 22, a female that is 18, my younger son whom is not African-American, and is now 16. My oldest Son, (19) fully cooperated with the police and yet was THE ONLY one of the five that was referred to as "G" and spoke to with blatant disrespect. He is also the only one of the FIVE that was honest, and THE ONLY ONE issued a citation for "possession of marijuana, less than one ounce" 1st of all, of course it was LESS THAN AN OUNCE, he wasn't the buyer (it was actually the 22 yr old) and it was IN REALITY LESS THAN $20.00 (a " dub") AND, there was also 3 bottles of alcohol that was also purchased by the 22 yr old male and the last I was aware, it is AGAINST THE LAW TO SUPPLY DRUGS AND ALCOHOL TO MINORS.

SO, tell me, first of all, why do police or authority figures of ANY type feel that they have the right to refer to a person by anything other than their name ?
2nd of all, why was MY African American 19 yr old son issued a citation and the marijuana taken yet the bottles of alcohol were allowed to remain in the vehicle, Police full knowing that the 22 year old OBVIOUSLY (and admittedly) purchased the alcohol not to consume all to himself,...... therefore, it is my firm belief that this was just one more case of Police showing prejudice at its best.