I think their uniforms are mostly polyester or something so they're slick, and the slide's angle is only safe if you're under a certain weight I guess.
My take: Start a company that markets slides as a "Quick Response" tool like firefighter's poles, install them in police stations with federal grants. Tout the "Tactical" black paint and Teflon-coated interior as a "Rapid Deployment Force Multiplier" that lets the piggies get to their surplus MRAPs as fast as possible.
Even despite that why was this guy going down it anyways? You expect this among a group of children in a sort of community service thing but there's like 0 people there.