Liberalism's Great Challenge?

[Jehanne]

Yes, you are referencing its etymology, not its current usage. Not even Aquinas's own church uses it in that sense.  

Obviously heresy is a choice, but that doesn't mean that is the definition, or current usage, of the word. 325 years ago a bureau was a writing desk with drawers. That doesn't mean that a government agency is a piece of wooden furniture.

If heresy was not a choice within Catholicism, then it could not be an excommunicable offense:

Can. 1364 §1. Without prejudice to the prescript of can. 194, §1, n. 2, an apostate from the faith, a heretic, or a schismatic incurs a latae sententiae excommunication; in addition, a cleric can be punished with the penalties mentioned in can. 1336, §1, nn. 1, 2, and 3.
 §2. If contumacy of long duration or the gravity of scandal demands it, other penalties can be added, including dismissal from the clerical state.

http://www.jgray.org/codes/cic83eng.html

Of course, under Pope Francis, there is no longer anything such as "sin":

http://www.charismanews.com/world/39644-...iversalism

This just shows that Catholicism, like all the other world religions, are natural and man-made, because not only do they contradict each other, they contradict themselves.