Final answer:
The complaint is about a ruler's tyranny and the use of foreign mercenaries during the American Revolutionary War, signifying a reprehensible disregard for the rights and lives of the colonists.
Step-by-step explanation:
The complaint is about a monarch, presumably King George III during the American Revolutionary period, who is accused of tyranny for using foreign mercenaries to wage war, committing acts of cruelty, and for failing to uphold the principles expected of a leader in a civilized society. Employing foreign mercenaries was seen as a problem because it represented a betrayal to the colonists, implying that the monarch viewed them not as subjects to be protected, but as enemies to be conquered. This kind of military action is particularly offensive as it suggests a complete disregard for the colonists' rights and lives, further justifying the call for independence and rebellion against such tyrannical rule.