You can always change your mind, it's a matter of how you handle the change (which they did very poorly). They provided a new option to get the game (on steam) without providering their preexisting customers the option to switch over. The fact they were confident enough to say for the longest time there would not be a Steam release begs to question their motives for releasing it on steam. Maybe the game isn't selling as well as they hoped, maybe they just want to scratch the bottom of the barrel for a few more bucks. If anything is for sure, it was not for the benefit of the customer. That is what people are upset about, they feel cheated and wronged.
So by that theory you buy a car that has a stock standard stereo system in it but a few months later the dealership offers and upgraded stereo system when you buy the exact same model. Are you entitled to an upgraded stereo because you bought it earlier ?? Get real!