The FI war was taught in the Americas quite a bit, and the colonies hadn't been paying any taxes to Britain before, so it seemed just to impose some taxes on them so that the colonists could pull their weight
The British Monarchy believed that it had a right to tax the colonies because they believed they were protecting the colonies from the threat of French invasion. The British believed that the colonists had to pay their part for the defense of their territories and the maintaining of security in their territories.
