Again I want to emphasize that you were comparing different algorithms on different data structures. It's like someone made a benchmark using the naive recursive Fibonacci definition and then you implemented the iterative version in another language and concluded from that that the other language must be much faster. The different algorithm is what gave you (most of) the speed up, not the language.

I mean, I don't doubt that C++ is in fact faster than Haskell, just not by that much.

Their criticism is fair: I have been making a performance argument. I do think they've misinterpreted my performance argument, though, which I'll get to. (There's a lot of backlog I need to catch up with; this thread is very large and my typing speed is significantly faster than the speed at which I can think.)