So I have to admit I am myself not really sure. It has been posted on r/haskell where recently there have been several posts about some kind of less-is-more approach when writing Haskell (for example [1]).

I would say it's some kind of informal manifesto to write Haskell code, that does not use too many or advanced features. The C++ community had and has similar discussions where people banned specific features and agreed on (admittedly different) subsets of the language. These endeavors have been more or less successful, but in general I agree that there is the danger of having a too powerful language, where people go off the board and write code that is hard to read.

[1] https://www.reddit.com/r/haskell/comments/eg25xt/a_plea_to_h...