If i'm understanding this correctly. The reason why everyone's upset, is because they think Microsoft is going to stop people from making programs?
I'll try to explain the situation as simply as I can but it's going to be a long post. Brace yourselves!
Right now, on Windows 7, anyone can made a Windows game and sell it through a multitude of ways. They can use Steam, Origin, GOG, Games for Windows Marketplace, Green Man Gaming or any other digital store. They can also do a retail release, or they can sell it directly from their website.
So this is the first important bit: Ability to sell a game whichever way you please.
Secondly, any game you make for Windows 7 wil be available to the entire W7 userbase. If you make a W7 game, anyone with that OS can run your game (assuming of course that their computer is up to par).
So, second important bit: Ability to target the whole Windows userbase with one product.
Now we come to Windows 8 and the inclusion of Metro, not just a different interface but essentially a separate platform within a platform. Why do I say that, you ask? It's because of the following fact:
Metro Apps (and games) do not work on anything else but Metro. If you want to create a Metro game, it will not work on the desktop, it will not work on Windows 7, it will not work on anything that doesn't have Metro on it. You will pracitically have to "port" it to these platforms.
So, first important W8 bit: Metro apps and games only work on Metro, so you can't target the whole Windows userbase with one product.
Let's look at distribution. I've made a metro game, how can I sell it? Can I submit it to Steam, or GOG, or Origin, or anywhere else other than the Windows Store? No. Can I sell it directly through my site? No. I can only sell it through the Windows Store.
So, second important W8 bit: Microsoft exclusively controls app/game distribution on Metro.
Of course people will say "so what? The desktop is still there, make a desktop app/game!". It's not that simple. Microsoft has divided the Windows experience into two separate parts: Metro (on Win 8 and Win RT) and desktop (on Win 8 and 7). They've also shown their preference on which one of they two they believe is the future of Windows.
Something like this has happened again in the past, when Windows replaced DOS. At first DOS was included in Windows and people still developed DOS apps (we called them programs back then), but Windows was the main interface and platform. After a few years DOS faded because everyone was using Windows apps and DOS development ceased.
Microsoft is going through the same transition, but this time they're not just replacing an aging OS with a newer one. They are trying to use this transition in order to gain more control or the OS and lock it down so that they can benefit from every app sold through Metro.
They are not going to discontinue the desktop any time soon because that would cause them a world of hurt with legal issues and anti-competition lawsuits. They just installed Metro as the main platform and they will simply wait until the desktop fades away to the point of irrelevance, since most people will only use the default interface and store.
I never said anything about buying the app. It would be free of course, just as Steam is free now.