I definitely agree that there are many examples of ineffective Haskell culture. As a Haskell contractor I get to see how a lot of different shops do things. One thing I can't really tease apart is that most startups have a lot of engineering culture problems, and picking Haskell doesn't inoculate you from that effect.
The main cultural issue I see specific to Haskell shops is that frequently rabbit holes aren't discouraged. By that, I mean there is too much of a tinkerer mentality where engineers are allowed to or even encouraged to experiment with untested ideas instead of known effective solutions. That is a habit I had to deprogram myself from too. It's very fun! In your spare time.
I hope we get to work together again! But I'm usually only called in if there's trouble, so maybe I shouldn't :^)