your logic is correct bu its confisung for the average Joe like me to see a poll with a global result higher than 100%It's not a bug. It's how multi choice voting works. If you ask 10 people if they like A, B, C, and D (allowing them to choose multiple values), and they all chose each option (40 "votes", 10 voters), it doesn't make sense to report 25% for everything. 100% of people voted for each option.
This method only seems confusing because it's a multiple-selection poll. If you look at a poll that only allows voters to select one option (e.g. http://xenforo.com/community/threads/handedness.1649) you will see that the percentages add up to 100%.I suppose there's an argument either way but I think this could be quite confusing.