I think the '1973' is supposed to be '1937', even though that is the title at this web page: https://www.max-ernst.com/the-triumph-of-surrealism.jsp - the text describes it as 1937 - and this style was a response to rising fascism, which presumably seemed disorienting and surreal - just as it does today.

Man, they had Stable Diffusion way back in 1937. Far out.