The point is you can't just bolt on H-M to a typical scripting language and expect it to work, like, at all. It's a pretty huge sea change, and it would warp the underlying language to the point where you'd just end up with some of non-lazy, non-pure Haskell.
The fact that Python allows you to do something absurd is simply an argument against its design.
Edit: Uh oh, looks like I ruffled some snakeskin!