Now, Old Tom. He's on record consistently demanding a complete and total political solution to slavery that leaves few, if any, problems. Was that an easy out for him? Who knows. It was optimistic at best, not feasible for 1800 at worst, and he acknowledges that the best way to end slavery is to instill in the young generation that the institution of slavery is unacceptable. He opposed haphazardly releasing slaves because it was open season on them to do so, as the later Dred Scott decision would prove. TJ wanted an actual solution, as he explains in his letter to Edward Coles. You have to remember that slaves were lucky to even have names, and addressing, what do they do when free?- was crucial.
His 'actual solution' was to deport or kill them or institute something similar to the segregation that actually developed. He also leaned more and more into this realm over the course of his life, in direct contrast to Benjamin Franklin in the previous generation or Abraham Lincoln two or three more down the line. Not an uncommon set of positions for the time period, but by no means universal, and certainly not laudable as an example of moral foresight.
Where does this information come from, the book mentioned in the OP? That's one book by a guy trying to stir up the pot. Which is fine, don't get me wrong. But I don't seem to see Jefferson saying that stuff - he did not want to cut them loose when there was nowhere for them to go and nothing for them to do, and since it was open season on them in the South to do so.