I disagree with that reasoning. All stories require conflict, and as a medium Literature and Movies are considered art, and without conflict they would have no story and thus lose almost all of what makes them considered art. A goal oriented structure is merely a way of clearly defining the conflict for the player's sake.
To get hung up on the name 'Game' is counterproductive to both your argument and the movement to create games as a viable art form. To get hung up on aesthetics such as semantics is a rather weak point. Comic Books were viably art before they gained the name 'Graphic Novels', a name change enacted only because people refused to purge an idea from their head.
However, I'd like to get to the meat of my argument, which is that the goal oriented structure of gaming is not an indication of it's lack of artistic integrity. While I'm not sure how you define art, I think that if you consider books or movies an art form, then you'll understand the importance of conflict. You'll also understand that games reach up to 10+ hours on average, thus requiring constant goal settings. The story must move on, and in a long stretching medium such as games have, with the disadvantage of not being able to rewind to turn back a few pages to remind yourself what's going on, goals must be implanted in order for the player to move the story along.
Should a clear pathway truly bother you that much, try a slightly less linear game structure. Every Day the Same Dream is a flash game that could help, or a Half-Life 2 mod, the Stanley Parable, is another good choice.