Very interesting flip! For much of his life, Dijkstra opposed functional programming. He even more strongly criticised FP from Backus and APL from Iverson, which are both very funcional/function-level.

As he said, Java is a mess and any sensible person would oppose the switch from Haskell to Java. I am almost sure he never used any of them. Might have read about them, but highly doubt he run any on computer.

As for the high-level status of Haskell and APL — both languages are very mathematical. Haskell goes very into the abstract realm of computation, while APL tackles very raw form of computation. Semantically, Haskell is way more high-level. In terms of economy of notation and unified concepts, APL has no match.