You are lying I'm afraid. You do not need to be logged in to vote. You can hit the POST method with zero authentication and register a vote. While you may not see the vote without being logged in, you can certainly vote as many times as you wish with zero accountability.
Care for another demonstration?
Much like you have a security code for this blog, you should have a security code for the poll. In fact, you should have to submit your security credentials to the poll itself.