Remember that Washington himself was a British soldier early on.
The seeds of Washington's discontent with the British (and in the 1750s, essentially all Americans considered themselves British subjects) was how he--as a colonial--was treated by British Army regulars. In 1758 he took the long ride to Boston to personally complain to General Shirley.
It was not until after the end of the French and Indian War (1763)--when the Brits started to tax us in order to recoup the great expense of defending us colonials. The first organized show of resistance--as you know--wasn't until the Stamp Act Congress held in NYC in 1765.
Duche was with us when he gave that prayer, but as the article states he wanted the RevWar to end in 1777 because of the hardships he saw his countrymen suffering.