Fo those who didn't read the linked thread, here's the nugget (answered by Ian Lance Taylor):

  > Why not just panic, though? And why the infinite loop, I wonder?

  The runtime is a special case in many ways, and this is among the more
  special parts.  This loop exists to catch problems while testing new
  ports.  If that loop is ever reached, something has gone badly wrong:
  the exit call should have caused the program to exit.  We can't assume
  that panic is working.  We can't really assume that anything is
  working.  What we want to do is stop the program.  Since exit failed,
  it's possible that a nil dereference will succeed.  If that fails too,
  we still have to do something, so we just loop.  We can't return
  because this is the main function that started the program; there is
  nothing to return to.