In a Twitter thread posted Wednesday night, Millsap relayed the incident, noting that current head coach Quin Snyder was present for the interaction.
Lindsey was the team's general manager at the time.
"It's an honor to stand up for what is right in any capacity," Millsap wrote. "Hundreds of thousands of beautiful black lives massacred for Truth, Freedom, and Justice. Damn right it sticks with you, but with Truth it will never overtake me again."
Millsap, who played collegiately at Louisiana and UAB, appeared in 67 games across two seasons for the Jazz before he was waived in January 2016.
He moved on and began an international career, with stops in Israel and the Phillippines, before he rejoined the NBA in the G League. He was called up to the Phoenix Suns, where he appeared in two games. He moved to the Minnesota Timberwolves' G League affiliate and then played 11 games in the Spanish Liga ACB in 2018.