Proffesional criminal hackers , will find their own security flaw and use it, without telling anyone.
Everyone is dependent on what is in effect an open source system, whereby security proffesionals and laymen worldwide, provide operating systems vendors details ,in private, of various exploits and the o/s providers patch them, hopefully before they become public.
in the end its a numbers game,the bad guys look where its going to be more productive, if they find a unix server vulnerability on a major organisations server , they will use that because that is where the big money is.
In the main part windows users are more prone to getting virus`s from script kiddies, or being phished than they are to a concerted criminal effort to glean my credit card information from a hard drive Basic security steps that should be second nature by now will cover 99.9% of all these eventualities.
However the writer of the max exploit was saying, that both Mac and Linux users should not feel that they have an invicibility cloak, and should both patch and use security measures in order to keep safe.
At the end of the day he is one of the good guys, and just because he managed to get through apple security you should not just dismiss anything he has to say out of hand.