I agree with those saying that Washington was affirming that he is pleased that the evil intents of the illuminati had not penetrated freemason groups in the U.S., and that their dogmatic evils had not infiltrated U.S. founding documents either. As was typical among learned men in colonial times, his language is quite formal, and his use of double negatives makes it even harder to understand his meaning–a practice that finally gave way to more clarity in the 1800s.