That article is definitely food for thought.
I disagree on one thing though. I think EVERYONE has that responsibility. If you think another pilot flies dangerously, you should say so. You can add that maybe you're wrong, that you don't have the experience, perhaps. But just say honestly how you feel. If he /she scared you, say so. Don't be confrontational, just be honest. Don't accuse the pilot of anything, just say you're wondering what was going on, maybe it's you who doesn't understand or know enough, but it worried/upset you enough that you wanted to discuss it. That way, it shouldn't be a big deal. And it might save someone's life.