Or at least by not being the shittiest, it's kind of a pragmatic balance, yeah some shittyness but only as much as they must incur for some publishers/developers to approve being in their ecosystem. Sharing a game library within a household is more complicated than I would like for example, owing to DRM restrictions. Steam has gone out of their way to try to make it more possible, but it's still a pain by its nature.
GOG takes a harder line that is easier for me, but misses out on a fair number of titles as a result. Which is why I prefer throwing the money at GOG to very strongly make clear my preference.

Yeah, AppArmor is a lot more straightforward. I could buy an argument that technically the SELinux approach is more flexible, but it's hard to imagine someone needing that much flexibility in the general use case.
I can understand why something like Android could get more mileage out of SELinux' model, but most scenarios are very capably modeled by AppArmor approach and much easier and less fragile functionality wise.