The only reason to not define them as art is if you have a strangely specific definition of art, such as defining art to only include things of a certain arbitrary level of perceived quality or appeal to refined tastes. I don't think "art" is really so special of a category that you can exclude stuff from it. There is plenty of really lousy art out there, after all. So obviously something doesn't need to be mind-blowing high quality to be art.
The word "art" really doesn't have much meaning at all. Everything is art. A child's scribbling hung from a refrigerator door by a magnet has equal claim to being art as Mozart's greatest symphony. Whether it is good art or bad art is irrelevant, it is art nonetheless.
The problem is that generations of artists, thinkers, and consumers of art have continuously co-opted the term for selfish purposes. Artists try to monopolize the term for marketing purposes; they try to elevate their works as "works of art" and try to diminish their competitors as "not art" to increase the relative value of their works. Likewise, wealthy consumers of art (including museums and the like) try to increase the perceived value of their collections by placing them on a pedestal and building up a perception that they have some inherent quality that separates them from more common, professional works. In reality, the only difference is a mix of semantics and what market they are buying and selling their goods in.
Furthermore, people have attached too much credibility to the concept of the "artist" as someone strange or special: a person of unusual genius and temperament who creates things normal people cannot. This is one of the empty myths of creativity. Most artists are just normal people doing the job that they like for a paycheck, and it has been that way since the dawn of time. Shakespeare was just an actor and a writer trying to create plays that would sell tickets to audiences. Leonardo da Vinci did most of his paintings on commission. Just because these men were talented and created great works doesn't mean that were somehow fundamentally different in nature from modern equivalents like television script-writers or artists with accounts on Deviant Art who draw for commissions.
By their very natures, videogames are full of art. They have images, music, stories, and cinematic elements. All of these are well-established forms of art, created by professional artists. Furthermore, the gameplay itself, which is designed to create emotions and experiences for the player, is to me a perfectly valid form of art in of itself. Art is a product that makes someone experience something. Anything, really. Videogames offer experiences, so they are art. Not that that term really means something by itself.
The only real question is how much further the videogame medium can still go as an art form. What new techniques will be created and what forms it will take in the future? What will be the great works that stand the test of time? What new artistic styles and schools will arise in gaming? What is the best path to creating better gaming experiences? These are the questions worth asking.
Too lazy to rephrase
