TJ wouldn't have been able to have that opinion if the Tradition didn't first exist, that he could "criticize" it in the manner he did.
TJ may be a sort of god to you; but I recall that when he died, he did not free his hundreds of slaves — except for five of them, who were likely his own children by Sally Hemmings. Sally herself he never did emancipate. He died a bankrupt, or rather "in the hole" (no pun intended) with something like $200,000 of unpayable debts — a whole ton of money in those days. Thus I gather he found the moral requirements of the Ten Commandments rather inconvenient to his preferred manner of living....
I think it's reasonable to conclude that, for all his diverse genius and accomplishments, TJ had some "personal issues" of a moral nature. Of such kind that the Bible stood as a living rebuke to him in certain regards. This being the case, I can see how he'd be inclined to sneer at it.
Then you would agree that our foremost founding father, Thomas Jefferson, did not live the Christian tradition?