I voted no and tried. It wouldn’t let me vote again. I always check. Maybe it’s only letting the yes votes vote again?
You just have to clear your cookies in your browser and you can vote as many times as you wish.
That's always the issue with these kinds of polls that require no registration, and/or confirmation of that registration.
You can (and folks do) have a secondary browser they only use for polls, and simply clear the cookie each time before voting multiple (often hundreds of) times.