This is an interesting concept... can an individual, or organization, declare "war" against a corporation and actively try to do them harm and/or destroy them as an organization?
Of course they can, big corporations do this regularly to the smaller corporations. But this "war" wouldn't fit any universally accepted definition of war so I don't know why would you want to declare anything, just do what you want to do. It is really interesting that a lot of people think that the best solution to any problem is to declare war to said problem, either real war or just "war".
When you go out to buy, don't show your silver.