The distinction is the legal entity. If an individual speaks, and has liability for that speech, it is entirely different from if an individual speaks, but only as a representative for a company, union, etc... This is simple and easy to enforce, but would give a huge advantage to individuals and small privately held business over large corporations in terms of rights, while corporations would benefit from scale and limited liability. As it stand, large companies get ALL the perks and none of the costs, and effectively have MORE rights than individuals.