Well if you can call USD, CNY, GBP, TRY,.... and the rest of more than a hundred fiat currencies being traded in Forex markets commodities then you can also call bitcoin a commodity.

The only thing that sets bitcoin apart (which is a temporary characteristic) is that its price is being decided in a rather small market that has caused a lot of volatility. Otherwise in the future when bitcoin reaches mass adoption and the market is not so small to be manipulated by the overly excited traders, its price will be stable too. By that time it becomes easier to see that the price depends solely on supply and demand, both of which will have reached a fixed and balanced state.