While I generally agree that functional programming does help immensely to make secure software, in this case, the function wasn't pure. It was meant to return

While I generally agree that functional programming does help immensely to make secure software, in this case, the function wasn't pure. It was meant to return data that didn't exist from a database, but the error was silenced. Also, the reason why the servers were "burning" was because this somehow resulted in a memory leak that consumed all the memory available to the system, which is why they also had trouble pushing fixes. Even in a pure function in Haskell, memory leaks are possible and the same scenario could've resulted.