He never call Win32 an "open standard." He calls it an open platform, or open experience, which he means anyone can build win32 games and distribute them on their own.

Using the word "standard", which he never does in that article, is quite misleading.

I don't think it's worthwhile to split hairs over standard/platform; I've heard Win32 called both, many times, by respectable sources.

As it is, he argued that Win32 is more open than UWP or Android; regardless of whether you think the API is a standard or a platform.

His statement is definitively true on the software distribution side. Google wants every App installed via play store and now even Microsoft Office is only available there. Classical Windows on the other hand allows Chrome to be installed without MS acting as gatekeeper.

Yes, it's not totally black and white. Android does kinda allow side-loading with shitty usability. MS did start its own store and lets not get into telemetry. Classical windows still gives the user a lot of control, though.

I would not claim that any of Android, UWP, _or_ Win32 are open.