As you say the Haskell version explicitly controls state, your python version doesn't. If the python version had access to the variables in question under lock

As you say the Haskell version explicitly controls state, your python version doesn't. If the python version had access to the variables in question under locks with as much security as the Haskell version then they would be doing the same amount of work. Sure they don't do anything observably different but it is a daft example with no driving motivation for why someone would write code that way.