I refreshed to see if the results updated and it seemingly let me vote twice. Does that show in the results (assuming you see a full list of votes)?
So your Id gets stored locally, just clicking on submit should not add another vote as is, but you can easily spam by doing so in incognito. For non spammy polls the poll creator should set a proof of work difficulty, or the poll viewer should filter the results only from the "people they follow" or any lists they might have added.