I think it depends on the point of view, as it can be considered a game for some and a sport for others, especially for those who make a living from it, so it depends on each person's conception!
It has elements of sports but falls short in some of the traditional aspects of what we generally deem as sports. It is however undoubtedly advantage gambling and for some its disadvantaged gambling. The advantage is generally derived from a level of experience and the ability to recognize and correct mistakes in your game.