The correct answer to this open question is the following.
In my opinion, what happened was that the American colonists were upset, tired, and desperate for freedom. They indeed were mad about the heavy taxation imposed by the English government such as the Navigation Acts, the Tea Act, or the Stamp Act, and many others. They felt that taxation without representation in the British Parliament was totally unfair.
That is why Thomas Jefferson, and the other four prominent Americans who drafted the Declaration of Independence, were not afraid to anger the British crown. They knew they were at a disadvantage against the powerful British Army, but they also knew that Britain was facing many conflicts in Europe, plus the colonists could not stand one more authoritarian decision from the king. Colonists were ready for the consequences and that is why the Declaration was written with that tone.
