Soft paywall, but here are snippets from the article worth reading:

##To be sure, there are layers to this story that make it way more complicated than just the “Coach tells fans not to boo, and fans boo anyway” headline.##

Layer one: The Spurs haven’t made the playoffs in five seasons, and have started with a miserable 3-13 record in a year that Popovich himself announced was going to be about winning.

Layer two: Leonard left the Spurs under a set of circumstances in which the average fan believed he not only quit on the franchise, but also betrayed Popovich himself. That violation was, and continues to be, deemed unforgivable.

Layer three: A not-insignificant portion of the fanbase is inclined to be outraged by anything Popovich says, due mainly to his outspoken criticism of their favored politicians.

Layer four: Politics aside, civil or not, there is a long history of sports fans venting their frustrations with opponents, and San Antonio never has been an exception to that rowdiness.

##The Return##

He also recalled that when Leonard and Danny Green came back with Toronto to play their first game in San Antonio, the team showed a tribute video and “the crowd didn’t react like that.”

But that’s not quite true. Back then, in 2019, the crowd cheered every time Green’s face was shown on the screen, but the jeers were deafening every time Leonard was shown. The fans booed him every time he touched the ball, and chanted “Traitor! Traitor!” when he attempted free throws. In Popovich’s defense, he said that night he “felt badly” about that treatment then, too.

##Way, way back##

From almost the moment the Spurs arrived in South Texas as an ABA team a half-century ago, they were known for housing some of the most rambunctious, unwelcoming fans in the league. In the 1970s, the “Bums” pelted then-Denver coach Larry Brown with avocados. In the 1980s they scuffled with Larry Bird after a game, prompting the Celtics legend to swing a duffel bag at them in what he claimed was self-defense.

Once, after the Bums heckled Kareem Abdul-Jabbar following a fire at his house, the Los Angeles Times called that segment of Spurs fans, “loud, doggedly persistent, and at times utterly tasteless.”

So this phenomenon isn’t new, even if the Spurs’ run of championships during the Tim Duncan era — plus the mellowing of the Bums in their new higher seating section — distanced them from that image.