My take is it's because there are some really great benefits to implementing things more precisely (which usually means "more general" in this sense), and Haske

My take is it's because there are some really great benefits to implementing things more precisely (which usually means "more general" in this sense), and Haskell is more amenable to it than most. There are many cases where it's worth it, so much so that it's worth at least considering whether a more generic solution is better. I think the problem is that it's hard to predict how deep a rabbit hole like this gets - so you think it's just a few minutes extra work, but it ends up completely derailing the project.