I'm not familiar with the other post. When you said the statement was made by "A Christian," I thought it was any old Christian, but then I realized you were referring to our friend.
I would not use 1 John 1:5 to prove that God does not have an intellectual knowledge of evil. This text reads: "This is the message which we have heard from him, and declare unto you, that God is light, and in him is no darkness at all." As "darkness" is here used as a symbol of evil, the text indicates that there is no evil in God's essential nature, not that God does not have an intellectual knowledge of evil. The writer knew enough about the previously written Scriptures to realize that God constantly condemns evil.
It looks like the original thread had something to do with the tree of the knowledge of good and evil. The Genesis account does not tell us what that tree represented, but merely uses it as the occasion to test the first couple's obedience. Some may say that the tree represented the EXPERIENCE of good and evil (a mixture of both), while others will say that it represented the right to determine good and evil for oneself. Does this conflict with God's later statement, "Behold, the man is become as one of us, to know good and evil"? No, for on the one hand, God's knowledge of good and evil was inherent and not based on an experience of good and evil which man supposedly acquired; on the other, God had retained the right to determine good and evil which man should not have tried to appropriate to himself.
Anyway, if we couldn't have a knowledge of evil, how would us Christians ever fight heresy?
Justin