What is Wind of Hate?
Basically close interpersonal aggression that one needs to face not just on the battlefield but during our daily lives. Grossman gives a lengthy description of this civilian hardship, let's just grab a line:
All of us have had to face hostile aggression. On the playground as children, in the impoliteness of strangers, in the malicious gossip and comments of acquaintances, and in the animosity of peers and superiors in the workplace.
It's not unknown to any of us and Bernds on KC main oftentimes cry about their anxiety if they need to go to the outside world supposing they have to face this Wind of Hate in all their interactions.
Some people just cannot cope with this and takes action.
Indeed, history is full of tales of soldiers who have committed suicide or inflicted terrible wounds upon themselves to avoid combat. It isn't fear of death that motivates these men to kill themselves. Like many of their civilian counterparts who commit suicide, these men would rather die or mutilate themselves than face the aggression and hostility of a very hostile world.
It has a military application:
Psychologically, aerial and artillery bombardments are effective, but only in the front lines when they are combined with the Wind of Hate, as manifested in the threat of the personal infantry attack that usually follows such bombardments.
This is why there were mass psychiatric casualties following World War I artillery bombardments, but World War II's mass bombings of cities were surprisingly counterproductive in breaking the enemy's will. Such bombardments without an accompanying close-range assault, or at least the threat of such an assault, are ineffective and may even serve no other purpose than to stiffen the will and resolve of the enemy!
[...]What maneuver warfare advocates have discovered is that over and over in history, civilians and soldiers have withstood the actuality of fear, horror, death, and destruction during artillery bombardments and aerial bombardments without losing their will to fight, while the mere threat of invasion and close-up interpersonal aggression has consistently turned whole populations into refugees fleeing in panic.
[...]The potential of close-up, inescapable, interpersonal hatred and aggression is more effective and has greater impact on the morale of the soldier than the presence of inescapable, impersonal death and destruction.