I find that hard to believe. After all, George Washington was "loyal to the King" during the French and Indian War as well and was still allowed to serve later for the Revolution. There was something else going on.
As I remember a book I once read on Robert Rogers said that Col Rogers was still owed a considerable sum of money by the British government. He was chronically broke, so he tried to simultaneously get the money he was owed by the British and offer his services to Washington. Also it was not a particularly well kept secret, so he ended up spoiling his relations with both sides. He also wanted assurances that land the Brits had promised him but never actually gave him title to would be honored by the new US govt. Eventually time ran out, the US govt lost patience with him and he was left basically holding a meager British offer. His Rev War exploits for the British were mostly forgettable.