Yeah a lot of people who like his writings have criticized that term. I don't really like it myself, but it kind of stuck. The word does refer to a real phenomena that currently doesn't have a mainstream name. So Moldbug gets credit for identifying the phenomena and picking some name for it. I'm not sure what a better name would be - the Clerisy? the Mandarinate? the Congregation?
But, it is a lot more accurate to see ideology and religion has basically the same phenomena, with belief in a deity being pretty much spurious, than it is to see ideology and religion as two entirely different things. So I give Moldbug credit for pointing out that progressivism is basically the same thing as a religion.