Maybe, but the response doesn't really explain for most of the cases why that is the case or why we should care for anyone that doesn't already use Haskell.
The target audience is r/haskell. I highly doubt the point of it is to explain anything to people that don't use Haskell.
That's fine, but as another commenter points out, while that's perfectly fine on /r/haskell, it makes it a poorer post here without additional commentary as to why these things matters.
It's a first-person source. You can gain more value from it than a third-person one, but it requires more work to get those advantages.
I agree with this, but I think the appropriate reaction is to ask what he's talking about rather than complain about self-promotion.