Because Washington is such a towering figure in our history, he has become the subject of much mythologizing and wishful thinking on the part of the Religious Right. Its leaders would like to claim him as one of their own. They're trying to retroactively baptize him.
MORE: https://www.au.org/blogs/wall-of-separation/falsehoods-by-george-religious-right-seeks-retroactive-baptism-of-america-s