Sure, you can hide and worry about protecting yourself in an ever more dangerous world, or join people like him and me and take a stand against bad behavior. If enough people do it, it will make a difference.
No it won't. You're not "taking a stand". This isn't a bar fight. You're mistaking responsible defensiveness for cowardice, and passive-aggressiveness for civil courage.
There is zero chance they'll recognise your dominance, let alone moral superiority, and walk away changed from a teaching moment. They're not even seeing you as a person. They only see your car as one more obstacle among so many other "idiots", and it's quite probable you're provoking only more reckless behaviour.
> you can hide and worry about protecting yourself in an ever more dangerous world
This is a childish mindset. It would be worth taking a defensive driving course if you haven't done so, it may be helpful.
> join people like him and me and take a stand against bad behavior
Ironically, impeding faster traffic by camping the passing lane is also illegal in several states (yes, even if you're going the speed limit).