I think some of the examples cited by the author make me more confident that kids shouldn't vote.

Specifically the fact that those with dementia can have someone assist them in voting. That seems kind of ridiculous to me, seeing how easy it is for relatives to take advantage of this.

If you aren't cognitively independent then you shouldn't be able to vote. Lower it to 16? That's not that outrageous. But allow a five year old to vote with their parents help? You're just giving two votes to a parent at that point