It used to be. Back in the 2000s, they were despised and for good reason. The jerseys were dinky and minor league. There was nothing legit about 'em. Along with the Rockets pinstripes and Detroit's abomination from the 90s, everyone laughed at how god-awful they were and how it fit such a cartoony franchise in a cartoony state like Utah.
It only became popular again because of nostalgia, where what is old and unpopular is now new and popular. But when the Jazz dumped the old mountain jerseys, it was met with a large, and supportive 'hell yeah' from most fans.
I don't believe anyone really likes these jerseys. They tell themselves they do because it reminds 'em of the most successful era of the Jazz and 90s nostalgia, like 80s nostalgia was when the Jazz dipped back to the note a decade or so ago, is in and popular.
The jerseys are atrociously dated and only good as a one-off gimmick. No matter how many fans try to convince themselves they're actually good.