Even his own daughter "never witnessed his private devotions" and "never witnessed his private devotions." Do you not think that, if he were a Christian, she would have at least heard him speak about his Christianity, at least in passing? Do you not find it odd that he did not?
"To say that he [George Washington] was not a Christian would be to impeach his sincerity and honesty. Of all men in the world, Washington was certainly the last whom any one would charge with dissimulation or indirectness [hypocrisies and evasiveness]; and if he was so scrupulous in avoiding even a shadow of these faults in every known act of his life, [regardless of] however unimportant, is it likely, is it credible, that in a matter of the highest and most serious importance [his religious faith, that] he should practice through a long series of years a deliberate deception upon his friends and the public? It is neither credible nor possible." Jared Sparks
Did Sparks have an agenda or do you?