Final answer:
The colonists in the film "A More Perfect Union" were fighting primarily about taxation without representation.
Step-by-step explanation:
The colonists in the film "A More Perfect Union" were fighting primarily about taxation without representation. This means that they were being taxed by the British government without having a say or representation in the British Parliament. The colonists believed that this was a violation of their rights as English subjects, as they were not able to elect representatives to the Parliament.