I get the feeling you didn't fully understand what larsiusprime explained, as you brought another example which isn't similar to the main issue here.
The primary key of the issue here is the loss of something that actually existed. The iOS App Store has never been open. You can dislike the lack of openness but there has never been an event that removed the openness, as it has never existed. The same goes for Epic's games. The console exclusive Gears of War 3 never had a PC version released and then subsequently taken away and buried ATARI style. It has always been console exclusive.
Tim sees Microsoft's actions as a force that will reduce the openness of the Windows platform.
He's not fighting against closed systems because they are closed. He's not fighting against closed systems in general for any reason. If he was doing this, then you would have a point. He is angry that the status quo of having an actively supported open Windows platform is being threatened. He is fighting against losing that. The new closed system is just the evil actor that he identified.
This is a classical case of loss aversion. [1] Tim would be at least equally mad if Microsoft decided to redirect all its efforts from win32 to cow milking. Would you then claim that Tim is a hypocrite for having drunk milk instead of actively boycotting the dairy industry?
Yes, you could make the argument that extremely black & white attitude is necessary, and that if you like some open system then thus follows that you need to fight against every closed system. Some people like Richard Stallman do this. However most people, like Tim, belive that a more gray world can exist, and tend to fight when visible threats manifest and otherwise spend their time on other things.
There's no gain to society from having an open platform (I can develop Windows apps for free only having Windows), and converting it to a closed one.
The transition of users from computers to closed devices like tablets and phones means now most people are only consumers and can't create anything on their devices. Except for selfies, that is.
All PC platforms should be actively protected from this closure.
If you think only a GPL OS deserves to keep that openness then you are ignoring the 98% of computers that don't run Linux, for IMO silly ideological reasons.
The point is that Windows was never open. Open platforms like Linux now exist. Something controlled by one corporation and built under a proprietary license cannot be open even if they allow users to install stuff without an app store.
Please use the same terminology as everyone else. Windows has always been an open platform (that is anyone can write and publish software for it without being coerced into some sort of a contractual relationship with a third party). This is in direct contrast to iOS, say, where if you want to publish an app, Apple gets to be your distributor and your curator.
Sweeney is alleging that Microsoft' current tactics are intended to stop Windows being an open platform, which, if true, will be very jarring for a lot of users and developers.
Windows has never been open source software. That's a discussion for another time.
You're arguing semantics. Windows definitely isn't open the way GNU wants things to be open. It may not be open like you define open. However Windows does have some open properties [1] that are at risk of being taken away. When we say open in this context, we mean those properties, not that Windows is licenced under GPL 3.
[1] The primary open property in question is the ability to build, distribute & run apps on Windows without even notifying Microsoft. The opposite of a walled garden.
After all Epic is also profiting from them.
Or it is only bad when the size of the pie isn't as big as one wishes for?