I didn’t research the details of this specific case, but the point is police unions are known to defend bad people who abuse power.

Also, the guy in the link above also has a 3rd incident in 2015 where he admits to assaulting someone and got a slap on the wrist. Also, it’s 2020, and cops have body cameras and police car cameras, so there presumably is evidence of a DUI. Highly unlikely that another cop pulled him over and cited him for nothing.