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?