Most games, as in, 90% of them, are about one thing only: fun. Fun is a very simple word, and can constitute a whole range of emotions, but that is ultimately what a game strives to be: fun. I can't say that's art based on the simple fact it contains artistic pieces (such as sprites/models/music). What is the message of gaming? Usually, there is no message. It's just fun. What kind of emotions do video games usually go for? Fun and excitement. If you try to branch past fun and excitement, like, for example, in adventure games which aren't necessarily "fun" in the traditional sense, you lose the game-ness part of the equation and it becomes nothing more than an interactive novel. Thus, gaming is limited in terms of artistic expression, and as such, games are not an art form. But some games could easily be art, but the medium as a whole? It's pretty one-dimensional and vapid and its only goal is to be fun. It's very hard for a game to break out of this very strict set of rules and still remain a good game, first and foremost.
