The modernists were the neocons of 20th-century art. They took a sound methodology - the questioning of conventional wisdom - and made it a dogma that brooked no opposition, even from reality.
Which is kind of at variance with the rest of the article which, rightfully, links modernist thought--such as it is--with the totalitarianism of the 20th Century. Indeed the sentence after the one quoted is:
They turned a fad into a political programme, asserting "we" as sovereign over "them". Though Hitler closed the Bauhaus and Stalin loved Corinthian columns, the modernist utopia fuelled fascism and communism and bred a tradition of stylistic authority still alive today.