> Mac OS X v10.6.8 or v10.7. Adobe Creative Suite 3, 4, 5, CS5.5, and CS6 applications support Mac OS X v10.8 or v10.9 when installed on Intel-based system
They work, maybe, they are not supported though
It means that if it doesn't work, Adobe won't provide any support
I wouldn't expect Adobe to support CS6 in 2020 on my 10.9 system either. What matters is whether the software works or not—which it does on Mojave, and on Windows 10.
you are not wrong, but Photoshop 5, released in 1998, works on Windows 10 because Microsoft made it possible
CS6 works officially from XP SP3 (2008) to the end of Windows 8 (2015)
It works unofficially on XP pre SP3 (2001) and on windows 10, almost 20 years later and it's guaranteed to work on the LTSC for another 8 years (last LTSC is from 2018)
CS6 on Mac is supported on systems that span from 2011 (OS X 10.6.8) to 2014 (when Yosemite came out)
On May 2020 Adobe updated the release notes on CS6 saying that "If you are running Microsoft Windows XP with Service Pack 3, Photoshop will run in both 32-bit and 64-bit editions. However, Adobe does not officially support the 64-bit edition and you may run into problems."
So they are still supporting it on Windows XP on their official channels.
Most of the problems with old applications in Windows come from installers using ancient techniques to detect the OS version
Most of recent Adobe software theoretically could also run on older windows versions (8 or 7 for example), but are not supporting old platforms anymore with the new subscription versions and recebtly dropped support for the LTSC versions of Windows 10, so probably keeping the old versions around is a smart move if they work well enough for you
People who bought licenses for old versions should be in their right to use them as long as they can
Which simply is for longer on Windows than on MacOS
> MacOS Sierra doesn't even work with Photoshop CS6
I'm not sure where they got that impression, but it definitely works!