Seems like it's saying that grace was not taken away from us by God, but that we rejected it. And that part on Original Sin and concupiscence, if I have read this
http://www.thecounciloftrent.com/ch5.htm right, then concupiscence is our ability to sin, while Original sin is about our predilection to sin.
'We' can't have rejected it, as we have made no conscious choice - my reading of the textis that God has withdrawn it as a consequence of Adam's actions.
Yet again, the sheer opacity and convolutedness of the argument leads me to doubt its value.
It is an allegory because it acts as a representation for the different origins of diff. sins.
Adam could be some caveman who found out about alcohol, liked what he tasted (same way they liked the taste of the Forbidden Fruit), and had more, eventually leading to the development of the gene that causes alcoholics to become addicted to alcohol.
But this makes no sense at all - one the one hand the argument is that, as the father of mankind, there is a 'natural law' that Adam's misdemeanours carry consequences for his children. On the other, the same people argue that both Adam and his misdemeanour are myths!
Not only is the core argument for Original Sin itself extremely weak IMHO, but the proponents of that argument then cheerfully remove a critical part of it and act as if it still flies - it's extraordinary!
And bear in mind that they say on the site that many theologians believe that Original Sin is necessary to resolve the problem of evil - i.e. without Original Sin the notion of the Abrahamaic God is indefensible.
So, to summarise the theological views we have so far:
1. Solving the problem of evil is a necessary condition for God (= Allah, Yaweh or the Christian God for this purpose)
2. The doctrine of Original Sin is a necessary condition to solve the problem of evil
3. The Withdrawal of Grace as a result of the disobedience of a father of all humanity is a necessary condition for the concept of Original Sin
4. The act that is directly responsible for the Withdrawal of Grace is mythical and did not take place.
By linking various logical statements from within the Catholic Church's own text together it appears that the direct implication of the Catholic Church's creed is that God, as defined by the Church, cannot exist.
Which makes this whole dicsussion more bizarre by the minute...
BFR