Uhm... i think art is about self expression first, and having a clear message second.
I think a big problem with games being art is just how controlled and manufactured the chain of production is, for certain big games, but that's also true of many big movies, and not as true for smaller games.
To me the idea of art is more about getting into someone else's head, and through the abstraction of their art, glimpse at something they couldn't express in a more straightforward manner.
If art was all about "Fascism is bad!" it'd be a pretty fucking pathetic medium of expression.
If you want to get inside someone's head, I would recommend becoming a therapist.
Failing that, a biography might be the next best thing.
If we can't even get that, then reading their honest words are still best for grasping their intentions and how they came about them. Language exists entirely for the purpose of "self-expression" - it is self-expression at its most streamlined, sans the distraction of aesthetics (unless we want to get into poetry). Fumbling around like blind men, which is what trying to understand someone through art is (especially audiovisual art, and a hundredfold more with interactivity), may be fun, but its completely at odds with the idea that the purpose is to have an idea expressed to you. Basically, it's admitting the process of trying to understand someone is more important than actually understanding someone. And to that I say, why stop there? Why not simply focus on the experience altogether, how a piece of art immerses and injects emotions into you, rather than a self-defeating goal of communication?
Here we see yet another case of a phrase, this time it's "expression", being warped into something mystical, when it's really the most universal, mundane thing you can imagine. An expression is hardly any different from any sort of action a human or a collection of humans may take. You do something (anything, or even nothing), it's observed and interpreted, and thus you have conveyed a message to another human being - you have expressed something. Even the dumbest animals express things constantly; they may even do it with nothing more than the colors on their fur or scales! We humans have developed language to make the expression process very streamlined and thanks to that we've managed to build societies as advanced as our civilizations, a feat I don't think we could have managed with cave drawings alone. And if the mere saying of words account for expression, what is creating sprawling pieces of art that take hours, if not days, to fully consume, if not an even greater expression?
And to the audience, all expression follows the same process. The idea that human expression is at ends with, let's say, the "triple A" model is based on the flimsy idea that multiple expressions (or input) cancels out the fact that something is being expressed (experienced). The reason for the confusion is clear: I'm focusing on the art, while the whole "self-expression" gang is focusing on the things that exist outside the art - the circumstances of its creation. There's no fundamental difference between a hundred people collaborating and one person doing it, much like it doesn't truly matter if the author is alive or if the author is dead (or, indeed, if the artist existed at all and we haven't confused a "naturally" occurring phenomenon for something man or God made); at the end of the day, they are "expressed" (read: observed and interpreted) the same way and the difference exists "outside" of the art / the experience. Of course, you can decide to care how the game you are playing is made, you can decide the history you've been told on how the piece of art was crafted is more important than the experience itself; people clearly do this, after all, the indie marketing brand exists. "Our game is art because it was forged in a *special* way. We didn't do it for
money (just prestige and fame). Let me tell you all about it." Maybe I'm suppose to care less about good graphics then. Seems like another scam to me!
This is putting aside that every input put into a (big) game's creation is still a human one (a "creative" choice, like any other), whether it comes from developers or publishers, whether an environment artist's vision is filtered through a director's (or vice versa).