The article isn't trying to claim either interpretation, it's just using it as an example to show that the GIL doesn't actually help protect users from concurrency problems. You'd be surprised how many people think that!
I used to think that it did as well, but then my C/Java brain kicked in and realized that couldn't be correct. I wrote this article to help others see it in action.
I did too. I even wrote multithreaded test programs to see if it was true: they would always give me consistent results on Python and Ruby but on Java and C data got clobbered as expected.
for example: "move money from one bank account to another bank account"
essentially the same operations in the same order, that need to be isolated (i.e. transactional / atomic) from concurrent threads performing the same operations.
I used to think that it did as well, but then my C/Java brain kicked in and realized that couldn't be correct. I wrote this article to help others see it in action.