If business owners had to place their personal assets at risk to back business risks, very little investment would be made. I would never pledge substantial personal assets to back business debt.  

Those people who take on the debt of a company are doing so to make money, and they know the risks (or at least should). If they make bad decisions, they loose money.  Any investor knows that the personal assets of owners are not on the table.  

Think of it; you own part of or stock in a company that goes bankrupt, and your personal assets are frozen/seized to pay debt holders of the company?