"We must reduce our volume to the simple evangelists, select, even from them, the very words only of Jesus, paring off the amphiboligisms into which they have been led, by forgetting often, or not understanding, what had fallen from him, by giving their own misconceptions as his dicta, and expressing unintelligibly for other what they had not understood themselves. … I have performed this operation for my own use, by cutting verse by verse out of the printed book, and arranging the matter which is evidently his, and which is as easily distinguishable as diamonds in a dunghill.” He claimed that it was easy to make such determinations because “there is internal evidence that parts of it have proceeded from an extraordinary man; and that other parts are of the fabric of very inferior minds.” He abstracted “whatever has the stamp of the eloquence and fine imagination of Jesus.” He relied on the “style and spirit” of the writings to determine what was “genuine, and his own.” When he found “passages of fine imagination, correct morality, and of the most lovely benevolence,” he judged them to be legitimate words of Jesus.
“READ THE BIBLE, THEN, AS YOU WOULD READ LIVY OR TACITUS. … THOSE FACTS IN THE BIBLE WHICH CONTRADICT THE LAWS OF NATURE, MUST BE EXAMINED WITH MORE CARE, AND UNDER A VARIETY OF FACES. HERE YOU MUST RECUR TO THE PRETENSIONS OF THE WRITER TO INSPIRATION FROM GOD. EXAMINE UPON WHAT EVIDENCE HIS PRETENSIONS ARE FOUNDED, AND WHETHER THE EVIDENCE IS SO STRONG, AS THAT ITS FALSEHOOD WOULD BE MORE PROBABLE THAN A CHANGE IN THE LAWS OF NATURE.” After numerous examples, he continues: “In fine. I repeat, you must lay aside all prejudice on both sides, and neither believe nor reject anything, because any other persons, or description of persons, have rejected it or believed it. YOUR OWN REASON IS THE ONLY ORACLE GIVEN YOU BY HEAVEN, AND YOU ARE ANSWERABLE, NOT FOR THE RIGHTNESS, BUT UPRIGHTNESS OF THE DECISION. … Because these Pseudo-evangelists pretended to inspiration, as much as the others, and YOU ARE TO JUDGE THEIR PRETENSIONS BY YOUR OWN REASON, and not by the reason of those ecclesiastics.”
It doesn't get any clearer than that and attempting to explain this away will only make the explainer look bad.
One other point needs to be noted. Orthodox Christianity believes itself to be the only valid path to God and other religions false. Jefferson, Adams and the other theistic rationalists didn't believe this, rather they thought, contra orthodox Christian teachings, all religions valid paths to God. That doesn't mean they thought all religions "equal." Appreciate the distinction: To the key founders the "end" of religion was virtue. As Franklin once put it if the "ends" (virtue) are met, the "means" (which religion you are) ultimately don't matter (because you still reach the top of the mountain even if you don't get there the quickest way), we could see how they could believe all religions valid. However, Franklin and the other key founders also stressed Jesus' moral teachings the best the world had seen. So if the "end" of religion is morality and if Jesus was the greatest moral teacher, then we could see how they would think Christianity "better" or "best" as compared to a number of other valid theologies (i.e., the quickest way up the mountain). Hence, most or all religions are valid, though they are not all necessarily equal.
And indeed when you look at the language Franklin, Adams, Jefferson, and Madison use when praising Christianity, they almost never suggests, as orthodox Christianity dictates, that Christianity is the only path to God, but invariably use comparative terms like "better" or "best" to describe Christianity. Mr. Knapton seems to recognize this when he writes:
9. Valid and equal. What I was doing was not changing his thought but, rather, providing an additional thought. Let me give an example. (man I feel like I’m teach grammar school) Thomas Jefferson may have thought that all moral codes to valid. However, he did not think they were all equal. He believed the Christian moral code to be superior to the others.
However, what he doesn't recognize is that this isn't orthodox Christianity. Jefferson, Franklin, and Adams might give Christianity an "A" as a religion, Judaism a "B+," and Islam and Native American Spirituality "Bs." An "A" is the best grade, but all of these grades pass. Orthodox Christianity, on the other hand, gives Christianity an A and all other religions Fs!
And a final note, I would add this syncretism that Washington, Adams, Jefferson, Madison, and Franklin believed in is far more heterodox than the theological universalism that Benjamin Rush adopted later on in his life. Rush, a Trinitarian, following John Murray, became a Universalist believing all would be saved. But he remained a Trinitarian and otherwise orthodox in his theology. As I understand his creed, he still believed non-Christian theologies were false (and hence would "fail" them) but that all would be saved through the universality of Christ's atonement. The Bible discusses every knee eventually bowing for Christ. And ultimately, Murray, Rush, and the other Universalists so believed the Bible taught non-Christians ultimately would be saved by through Christ, even if, I suppose, their conversion happened after death.