Mac was on my list of highly secured OSes when it comes to viruses and other forms of attack.
But it's obvious that no system is completely safe and immune; those hackers just have to make it their primary goal to develop something that they will use to penetrate any form of OS they want.
We just have to take charge of our own security and think about the kinds of things we integrate into our system, like extensions or whatever they might be.

If this has been going on for over 2 weeks, who knows how many have fallen victim to this scam? Since they will completely gain access to every crypto-related extension and app on the affected victim's PC, they will probably move out any valuables on those wallets.