Are all types of internet voting unsafe?

IEEE, like many other professional organizations, uses a third-party vendor to conduct elections over the Internet to elect its leaders. After all, as scientists and technologists, we know the risks of online voting better than most. But then I remembered the key differences between public elections (those run by governments to elect leaders, decide on referenda, and perform similar actions) and private elections (those run by private organizations to elect their leaders and perform other activities):