It doesn't fit "pure", but it solves the same problems the article is talking about, as other functional programming languages do.

In fact the article is excluding most functional languages by saying "pure", and then goes on with "Of the top dozen functional-programming languages, Haskell is by far the most popular" under the graph, which is wrong because it's missing "pure", a feature that is _not_ required to solve the problems that are being talked about.

So I agree on the initial point "Makes me suspect the article is not very well researched."