Benedict is not concerned to burnish the reputation of St. Thomas as a "fighter for freedom of conscience", as though the saint's importance can be found in laying the groundwork for the First Amendment. In fact, the worldly reputation of More is of no concern to Benedict, as it was of no concern to More. Indeed, More was not fighting for any worldly goal, freedom of conscience, or otherwise. His great witness was to the fact that there are some things that transcend worldly goals, and are not negotiable in their terms.
The secularist cannot see that the appreciation of a saint is not about a careful weighing of the plusses and minuses in his life. It is about the window into the transcendent that the saint reveals; sometimes in the broad manner of her life, as in St. Therese of Lisieux; but sometimes also in a moment of dramatic crisis, as in the life of St. Thomas. Thomas was a man immersed in the cares, problems and compromises of his time; the secularist wants to judge him in terms of his decisions on these worldly matters. But the important thing about Thomas is that, despite his immersion in the world, he never became of the world, which the secularist is by definition. This is why St. Thomas is important to Benedict, and why he should be important to us.