I was reading David McCullough's 1776. I think America had always had somewhat of a backwater hick reputation to them.

Members of the British parliament, in particular the pro-war Tory faction, considered the Americans spoiled children. They were protected by the King, His Navy, His Army, and these colonials dare rebel? So the idea of Americans having no common sense or decency has always been around.

The thoughts of British soldier in America varies. A lot of them were stunned to see America, a land of great bounty and space, was upset by the British rule. American colonists, on average, enjoyed better standard of living than their European counterparts. Not to mention land was abundant and cheap unlike how every parcel of land in Europe was pretty much carved up between nobles.

Another British account how hypocritical the colonists seemed since many of them seemed pious and descended from puritans yet had plenty of prostitutes and red light districts.

Even among the Americans themselves, there was a lot of regional rivalry and disdain for order. Soldiers didn't like to clean themselves, officers were elected by popular vote rather than merit, and American soldiers thought highly of themselves and lost pretty much every battle in 1776 except for Boston and Trenton. The disdain for order in particular didn't bode very well for the military since it was the primary factor in how badly diseases ravaged their camps constantly during 1776. Men would abandon their post to go hunting. They relieved themselves where ever they want. Most refused to clean themselves or wash clothes thinking it was women's work. Also prostitutes. Lots of prostitutes.

tl:dr - America has always been somewhat viewed as backwater hicks.