Probably because the Haskell community is used to having a programming language that is, in and of itself, very good. They complain because they know what they're missing when they have to use inferior tools.
>Develop an imagination. Javascript can be wielded very effectively. It's just different.
The same can be said of x86 assembly. That doesn't mean we don't complain about programming in it, and we don't try to find better alternatives. The entire field of programming language development is about finding tools that are better than the old ones, even if the old ones work OK.
>The disadvantages are alleviated by comprehensive functional or black box testing.
If you think "more testing" alleviates all the problems of weakly typed languages, you have no idea what you're missing.
>I feel liberated by not having a strong type system restricting my options.
If you feel restricted by a type system, you're using it wrong. A type system is a useful tool, not an impediment. It only prevents you from doing wrong things.
"I like assembly because it lets me do any operation on anything."