The American Revolution was more than justified; it was necessary. John Locke's social contract theory was that people have the right to rebel against a government that is not doing their job properly or attempting to take absolute power. Britain had failed to secure America; Britain tore them down by restricting them.
The Founding Fathers were justified in rebelling against the Britain because the government was not protecting the rights of the citizens, taxing the colonists, and forced them to house British soldiers. In 1756 Britain put the first tax on the colonists.