It's a guide to hardware that lists the different hardware security programs, which Windows and macOS have. QubesOS however is purely software, so why would it be mentioned in the first place? It's listed in plenty of more appropiate places and is actually recommended as an operating system opposed to Windows and macOS.
Interesting. I knew about their hardware compatibility list, but not their list of certified hardware list. Their list of requirements looks quite a bit different from those intended for a regular OS and is (unsurprisingly) tuned for Qubes, but considering that it'd make sense to mention them, particularly if the user intends to run that.