Because in a way the people you are decribing are imposing their views on others . Sometimes these people come off sounding ‘preachy’ and ‘all knowing’. I’ve run into this quite a bit, either in business situations or from door-to-door religious salesmen. To impose or air one’s personal religious beliefs without being asked to do so comes off as rather arrogant in my opinion. It’s can come off as a’my way or the highway’ attitude.