Why was oj simpson acquittal such a big shock?

OJ simpson is not the first person or last person in this country with powerful evidence against him who was not convicted. Yet I feel that because he was a black male accused of kililng a white woman is why this sparked such an outrage. Had his wife killed him instead and not been found guilty I dont think it woudl have been an outrage. Also how bout the tennessee wife who killed her husband who was a minister she did not even get a year in jail and no one complained. Also why is there no one to complain when racist cops and racists kill black men everyday and are not brough to justice as they should.