I am, mostly because it's wrong and helps in perpetuating misconceptions. I use a PC with Linux, you can use a Mac with Windows or Linux (and others), and nowadays Macs are PCs with a prettier design, so saying "PC and Mac" is completely meaningless. It's like saying "Mobile phones" when it only works in Android. You then have to take the time to explain to normal users why it doesn't work in their iPhones or Blackberries.
As someone who happened to use Linux on their PC while coming across this submission, I was confused for a while as to why the download button was disabled. ;)
Ah, thank you. I've been trying to work out why no one seemed to be mentioning it. I flicked to Chrome, used a proxy ... still greyed out without any explanation.
Google are seriously bad at web design and copy writing it seems based on this.
I think this metonymy helps reinforce the idea that there isn't a conceptual difference between hardware and software, or that they are inherently a single integrated product.
If you value various aspects of keeping hardware and software separate, then not reinforcing this association -- and instead trying to draw the distinction -- is valuable.
A lot of people in a discussion like this will point out that many computer users don't know what an OS is in the first place, or don't draw any distinction between the computer, the OS, and the browser. That's true, but avoiding using the individual proper names of these things makes it even more true!