Why were the Americans justified in fighting the British?

In regards to the Revolutionary War; the Americans were justified in fighting the British Crown due to the fact the British had been forcing several acts upon the colonies to make up for money lost in the French and Indian War. However, colonial backlash to these acts came from British Parliament and the King refusing to allow the Americans any say in what laws governed them. After clashing at Lexington and Concord, the Americans drafted two documents. The first a request to the British King stating they would stop resisting if he gave them the rights they asked for, the second was a document for the King station they would be leaving British to form their own nation; should the King refuse to meet their grievances.

King George decided ultimately to not meet the colonial requests. Thus enacting the colonists going forth with the Declaration of Independence. British oppression and inaction to colonial calls for freedom resulted in the justification of Americans fighting the British.

"That whenever any form of government becomes destructive to these ends, it is the right of the people to alter or to abolish it, and to institute new government"