Re: "What happened to the "Linux is malware-free" claim?"
At the risk of making a troll happy, I don't remember ever hearing that claim. And no one in IT beyond perhaps L1 Helpdesk cannon fodder truly believes that any OS is immune from malware. What you would hope though, is that when you install an OS on your machine, it is at least initially free from corruption, and in this case, some users got infected downloads. Not the first time this has happened on the Internet, not the last for sure.
"Out of the box", Linux is generally less likely to be infected unless the user is prone to turning on all sorts of unnecessary services and installing software from shady sources. True, part of the reason is that it is not targeted as much due to the lesser market share. But as a Mint Linux user, I can honestly say that even if the Windows and Linux roles were reversed, with Linux being equally or more prone to malware than Windows, I would likely still use it due to the lack of bloat, marketing, pointless features that no one will likely ever use, and the general elegance of it. Like taking your vacation by a scenic lake instead of Disneyland. Though to each their own.