Own Your Business Vs. Other People’s Business

If you have extra sum of money and spare time, should you start your own business or should you invest the money to other people's business (i.e. public stock/bond markets)  According to an investment guru, you should do investments instead of starting your own business.  Why is that?  He replied, "A business operation has business cycles, however, you can always pull out your investment with a push of a button, without any moral obligation."

What do you think?