To support its self-regard, the elite needs to associate itself with whatever is uncommon. In the arts, for instance, the elite patronizes just those artists and designers whose work is inscrutable and even repugnant to everybody else. Thus the modern phenomenon of the avant-garde. But, elite snobbery expresses itself in moral as well as aesthetic taste.
Just as the elite patronizes the artistic avant-garde, it also supports what at any given moment pass for avant-garde attitudes, preferences, and lifestyles. The actual content of whatever ideas the elite embraces matters little because these ideas never serve the elite as anything more than fashion accessories. Outré ideas, ideologies, philosophies are easily embraced because easily discarded. The more perverse-seeming the idea, the greater its potential for displaying the elite’s extraordinary discernment. Thus, the same class of people who lauded Marcel Duchamp nominating a urinal to the status of art in 1917 today support a man nominating himself to be a woman and vice versa.
Progressivism has a longstanding association with snobbery, going at least as far back as the female-run salons of the 18th century that nurtured Enlightenment thought. In that particular instance, fashionable ideas did ultimately have unpleasant consequences for the silly blue bloods who entertained them, proving that the world is not entirely devoid of justice.