Threat generation and changing a monster target are distinct effects.
AddHate can add threat with zero damage, or reduce existing hate when its configured power is negative. The amount comes from the effect parameters. This handler acts on attackable NPCs; do not infer player-control behavior from a monster taunt.
GetAgro can direct a monster to attack the caster and recruit nearby NPCs from matching NPC clans within their help range. Its success setting is separate from damage. An instant target change does not guarantee permanent ownership of the monster attention.
RandomizeHate chooses another creature already in the monster hate list, excluding the caster, then transfers the caster hate. With no alternative target it has no effect. Individual skills may use other effects or additional checks.