It's not him who's disturbed. But he likes to disturb others--to shake them out of their rut.
Your happiness depends on your ability to balance the opposites rather than sticking to only one of the truths while ignoring all others. When you avoid something for long, over a period of time, it creates a craving in you that can disturb the peace of your mind and make you suffer immensely.
Every difficulty slurred over will be a ghost to disturb your repose later on.
It's disturbing to people that the small David can disturb the big Goliath.