"Just Culture" as mentioned before examines every aspect of an incident or abnormal event, not just looking at the controllers actions but also examining the companies procedures and management in an effort to prevent a reoccurance, exactly as it should work.
If the controller took some actions which led to an incident then they will of course be held to account, just as management will be if their procedures are poorly designed and had an impact on the incident.
In some companies where the investigations were purely "punitive" i.e. the controller is always wrong, find some way to blame them and then move on, it is more difficult to accept "just culture" because they (old management) cannot accept that their procedures or poor management could possibly lead to an incident.
until there is a shift in attitude some companies will struggle to adopt a just culture when it is still easier to lay blame on the controllers.