The correction officers' union is fuming over Colin Kaepernick's visit to Rikers Island Tuesday.
The former quarterback is best known for kneeling during the national anthem to protest racial inequality and police brutality.
He currently supports the organization "100 Suits for 100 Men," which donates clothes to the families of young people in custody.
Kaepernick asked to visit the inmates while he was in town this week to deliver a message of hope and inspiration.
A spokesperson for the Department of Correction says it doesn't cost anything to have someone deliver a positive message, nor is it unusual.
However, the president of the Correction Officers' Benevolent Association called Kaepernick "anti-law enforcement."
He said the visit will encourage inmates to attack correction officers.