If we're going down the "young people aren't yet mature enough to make a responsible decision" route, should we not restrict voting to those with, say, appropriate qualifications? Or perhaps at least we should make sure that all voters have read the manifesto and demonstrated an ability to understand and critically evaluate it.
Or maybe that's all just stupid, and we're mixing up the *responsibility* to vote with an informed choice with the *right* to have a say in the democratic process. And once that's settled, it becomes entirely arbitrary whether it's 18 or 16 or any other age.
Again, I can't say it bothers me one way or the other. But trying to argue that it can't be 16 because of some generalisation that such people aren't mature enough or informed enough, while overlooking that so are rather a large number of adults -- or, worse, trying to argue that you shouldn't allow a bunch of lefties to vote -- is just mistaken reasoning.
Let it be 18, or 16, because either answer is entirely arbitrary, and equally justifiable.