I agree, but it is fine to do so in safe states — where your vote is not going to make a difference. I live in a swing state, so I had to vote Clinton, like playing a game of chess, but if I had other options, I would have taken them. I agree with most of what you’ve stated, and I’ve advised many millennials in many of the same ways that you have. But I also do understand their desire to not vote for someone whom they don’t believe in. You call it political immaturity, and yes, given your international experiences, I can clearly see why you would term their refusal to participate or go third-party in such a way. But…it could also be that they’re principled. It could also be that they are that little trickle before a tsunami of change, that is desperately needed.
I’ve conversed with many whom are wanting to make a statement by voting for third-parties and write-ins, and I do think this dissent is important. (But only in the safe states).
They have to let the system know, they aren’t sleeping at the wheel (or waiting idiotically in the car to be slashed by monsters). They are awake and aware and still wanting real change and progress and not backing down.