You can't just label everything as "doing business" and then regulate it all. If I make something interesting and give everyone in the world the blueprints so they can make one themselves that's not "doing business".
Much as I ardently support FOSS (and similar: open hardware, say) I also think this idea has some use and deserves substantial consideration.
It is difficult to draw the line here, much more difficult than it seems at first, in my personal opinion.