My initial thought was that he was off his nutt.
I think that deep down, this vampire has conflicting sums to all of his whole, at the very least I suspect his ability to derive Biblical lore and the Bible and Jesus not eating pork may be giving him too much credit by the way in which he acts and the way he has his own personal prophecy that seems to be revolving round his head before he was turned. I think he heard his own messages at sunday mass and it was tuned to a different frequency than his father/preacher.
I think he had a strong driven persona and the demon didn't fully evict it, that a bit of the mad man soul remained that the vampire could not evict, so early in the turning before a battle of wills could start, it worked with what it had and gave him some ley way with what he believed were absolutes...from his faith to his common/favorite meal?
Maybe when your nuts like drusilla and this guy, your soul is corrupted and you hang on to it somehow? I don't know, but this seems to be what instance suggests as far as Joss vamp lore goes by what it provides in example.
He was, by my guess, calling them something he ate alot in his life, Pork and beans. His mortal self is either mad enough or strong enough to hold on to his mortal souls memories and actions that he retains something like a soul, he is dismayed when he is burnt by a cross. If a vamp was in the driver seat completely, why would it bother with things rooted in faith and forgiveness. Why would it even bother questioning instead of just taking note of what hurts and what doesnt. The memeories are a tool to the vampire, not what totally defines it?
I don't believe that in this case the memories are a tool for the vamp, so much as they are directing the vamp. The demon seems not to be in charge of the hybrid, it seems more of a by-brid. That, like William and his need for love that steered Spike to some odd results...(like seeking out a soul)...this memory/soul imprint or need impressioned this vampire into spouting nonsense and wondering why crosses hurt.
Madness seems a dire need for something, something that can maybe buck the demons sway on the hybrid (after all Drue was mad, not the thing that took over for her)
Perhaps thats why Angelus was such a perfect monster. LLiam did not want acceptance from his father, only to punish him for never asking what 'he' wanted. he started out a gready, debaucherate, a prodigal son who was not welcomed back.
What better host for Angelus to take the reigns complete?
