Uninformed voters are a fact of life in Democracy.
I see no difference, frankly, between some know-nothing college kid voting for the guy because their friends are than the know-nothing churchgoers who got wrapped up in a similar phenomenon with Bush, or the know-nothings at McCain's rallies who declare that Obama is an Arab or terrorist. Should they be voting?
If you believe in Democracy, you have to believe that everyone has a right to vote.
It's up to the campaigns to persuade low-information voters as well as those who do their homework.