Not that strange really. Having met ad designers, all they know is Macs, so they couldn't imagine using anything else than MacOS.
Maybe HP's advertising Hackintosh compatibility?
I mean, that tracks; it's the company that launched a laptop called the "Envy" that looked like a Macbook clone.
What bothers me more is the use of only two ellipses leading the tagline.
It could also be running Linux tweaked to look like macOS.
Bringing Occam's razor into the mix, it may not not be a Bootcamped Windows install running Mac in a VM running Windows, which is running a browser-based MacOS emulator.
Healthy hardware competition under macOS improves the chance of growing bigger those arrow keys the Macintosh SE used by Steve Jobs used to have for modern Apple keyboards.
I’m not clear what you are missing, but I miss the floppy drive that ripped the disk out your hand.