On the topic, AsA can blame the controllers involved all they want. It doesn't change the fact that best staffing practice dictates that in aviation, you have spare people on standby to cover the shortfall when people do go sick. Sickness happens and if your only plan to cover it is to get people in on their day off, you will end up with service problems.
Why the rest of the aviation world does it as standard but our magnificent 'leaders' can't see that it is necessary is beyond me!