And by the way, George III wasn't a tyrant. He was a dullish constitutional monarch.
For better or worse, the US argument was with the British government, whose policies were defined by its prime ministers and their cabinets, who themselves were elected by eligible voters among the British people to act as their representatives in parliament.
The US colonists disputed the British government's right to tax them without their consent. The amount of the tax was not injurious. The tax was used to defray the cost of defending and administering the US. Americans wanted a say in the decision-making about the country they inhabited.
One can argue the merits of the colonists' position without setting up a straw man tyrant as the person with whom they were arguing. For myself, I am glad Americans won their independence. But I don't see the revolutionaries as holding all the cards in the political argument between Britain and America. Indeed, looking back on it, it is clear an accommodation could have been found involving taxation and representation if both parties had been willing to seek one.
But essentially, enough Americans wanted to be independent that a war was doomed to occur. The pretext that George behaved in a tyrannical fashion isn't so much the explanation for the revolution as the desire of many colonists to become masters of their own fate. Which is a wholly reasonable thing.
But the need to paint one's opponent as a villain suggests a flaw in one's own case. Once the preamble was written, the argument Jefferson presents for American independence isn't as candid as it might be. The revolutionaries were guilty of lese-majeste and had no honest argument to make against it, even if they thought their demands for independence were more important.