(Consider this my acceptance)
Corporations are totally necessary given the nature of our financial systems, and our sue happy society. They motivate people to invest money in situations where they would normally be too afraid of the risks. The sole purpose of a corporation is to limit the liability of the investors.
If you're a multimillionaire, and you invest a substantial portion of your net worth in a sole proprietorship (by starting one up and being the owner), and that sole proprietorship gets sued for more than the value of its assets, the law could come after your personal assets. That means one day you're a millionaire, and the next day one of your customers spills coffee on their lap, and you're totally bankrupt.
Another possibility is if the business takes out some loans, and then there's a market crash. If it's a sole proprietorship, then you have to pay those loans out of your own pocket. If it's a corporation, then the corporation declares bankruptcy and probably goes out of business, and you lose the value of all the stocks you own in that company, but the bill collectors can't come after your personal assets.
My point is: without corporations, most rich people would never invest their money in any business venture, and our economy would come to a screeching halt (if it hasn't already). Motivating people to invest money is the most crucial part of a capitalist economy.