For me I think it is those who think they can make money so quick by investing all their money in Bitcoin that will think bitcoin is a game, because they feel they can be lucky to make good profit from Bitcoin.
I believe Op is considering Bitcoin as a game because there is danger involved. And if someone misses any investment, he will be game since all investment is subject to rules, and all of them carry risk. I believe @Rockstarguy when he refers to bitcoin as a game without any business or investment. This implies that the coin will remain stable and not fluctuate, unlike long-term investments that yield daily profits. Because you can never invest in bitcoin now and declare you would gain enormous return, he will absolutely hard to get profit in bitcoin when you invest for short term. So, in my opinion, anything that is a long-term investment cannot be a game, and I do not believe bitcoin is a game. If you can call trading a game, I would probably say yes because it is a daily profit because it is the only game you will play and cash out once rather than keeping it for a long time before you generate profit.