It's not distributed by Microsoft either, it's distributed by Win.rar GmbH from their own website. The developers made it only for Windows, but that doesn't mean Microsoft played any part in it. Windows is the most widely used desktop OS, especially in business environments, and selling to businesses is where WinRAR makes their money.
Also, 7zip 4 lyfe
I still can't connect my 360hz monitor and 165hz monitor and get HDR at the same time in Linux. Only two of these things work at once. Hoping the eventual new Nvidia drivers fix that, but otherwise I'm out of ideas.