That's akin to suggesting that a publisher won't release a game on AMD because AMD don't support NVIDIA gameworks... That is not how the PC community/industry works. If Oculus wanted to support steamVR (et al) then the appropriate step is simply to do that, and state that they can't support ATW via that platform.
Leave the choice up to the consumer, rather than create a situation which is potentially damaging to the future of the VR industry...
Who is going to invest in a new VR company if they know that N% of their customer base are forever locked into Oculus hardware?
The Rift works fine with SteamVR - I don't understand the point you're trying to make?
The Vive however doesn't support ATW. So if anything, the Vive is the one which is limiting access to something as it doesn't have those features. As it doesn't have that "feature" many of the Rift experiences in the Rift store play nice with it - that's not Oculus's fault.
If someone writes a game for Windows, which includes a feature which doesn't exist in Macs, i.e. Horizons, that's up to Apple to sort, and as per FD's store, you can't buy Horizons for the Mac.
In the same way, the Rift experiences use a feature which doesn't exist on the Vive. That's up to HTC to sort, and as per the Rift store, you can't buy those experiences for the Vive.
I don't see the problem with Oculus only letting Rift users use Oculus home as that's designed for their hardware, for their customers. Their customers can use SteamVR like the rest of them. HTC didn't go with their own "store", and are doing it through Steam - that's their choice - why should Vive owners get access to Oculus home? That's like complaining that Windows users don't get access to the Mac App Store.
Your assertion that it's "not how the PC community/industry works" is incorrect - there are plenty of instances of proprietary hardware/software which don't play nice with other manufacturer's hardware/software which essentially does the same thing. That's just competition, which is part of business - this isn't some altruistic race to better the human condition - both companies want to make money.
People won't invest in a VR company which doesn't a) make money on the HMDs or b) have a lock in mechanism to provide guaranteed income from users in the future. I hope HTC are making money on the Vive kits, as without a dedicated store, they limit their income and are a peripheral manufacturer only. Oculus has played the game better in this regard, as they're trying to build an infrastructure and retention around their device, which provides better prospects.
Currently Rift owners get the best of both worlds. For stuff which is on Steam they can buy and play it on Steam (and in their Vive too if they have both), and they can buy stuff on Oculus Home. Vive owners only have the Steam option, but that's not Oculus's fault, nor can you blame Oculus for limiting customers in Home to those who own the Rift hardware.