And it might be more: the number of [Voted For Something Else] + [Didn't Vote] + [Not Eligible To Vote] is probably far greater than 49% of all residents.
It is, but for many of them they really should be excluded. How exactly is a 2-year-old going to make an informed vote, after all? How is an infant going to even fill out the ballot?
I would argue, however, that prisoners should be able to vote.