They don't have a choice but to be pessimistic...they are trained and taught by the GB to speak negatively about life and how nasty the people are.
Don't forget their main purpose is talk how bad the world is and how the kingdom of god will fix it all.
Try asking any JW if they preferred to live at any other time in man's history.... they won't give you an answer because they know they enjoy
the present time.......best time in man's history.