Because they have no life experience, and at that age most teenagers think they know everything, the brain hasn't matured enough to be able to have a say in who runs the country
Oh, just stop it! How much has life experience really helped things. Old men running our countries hasn’t been particularly beneficial in the past. I’d rather see some young people expressing their opinions and running the country, after all it’s going to be their home long after we have gone and they may be less susceptible to the “no that’s mine” culture that a lot of us older kiwis vote for!
personally i think old people shouldn't be able to vote, they are brain dead and probably have dementia. like you.