So basically, they could have said God Is Appleness with exactly the same logical basis, (by equating Appleness with Existing) and used it to defend their own dogma concerning the eating of apple pie (With or without cream?), while saying the Appleness of God and the Appleness of a pie are actually totally different things?
Maybe I misunderstood it, but it really sound like they didn't really had any argument and had to invent something.
No, that's more or less accurate.
Giving them a fair shake, there
are ways to "defend" the bible without resorting to linguistic abuse of that sort, but none that preserve the claim to literal truth of biblical text that many, probably most, Christian sects cling to. An ordained priest, though very, very radical, and bible scholar I knew (One of my teachers) held the position that while the biblical texts
are true and divinely inspired, that truth is not
historical (or at the very least mostly ahistorical); it is of a existential (relating to the nature and means of human's place in reality) and moral nature. Not even remotely less important because of it, but not a literal, word for word, absolutely historically true, truth. This isn't denying the religious importance or weight of the bible, merely changing the focus; it's especially good for integrating biblical stories and lessons into the modern world, where much of the historical trappings of the bible are flat-out obsolete.
But, put simply, there are
absolute (completely inescapable and irrefutable) contradictions in a literal interpretation of biblical text (and Christian dogma). God
can not be good in the way humans are good, with the given discussion, (There can not be even resemblance between those two goods!) and be both omnipotent and omnibenevolent in a reality where evil, pain, suffering, etc., exists. In that situation, where evil exists and the goodness of God is even remotely resembling the goodness of man, either God is not omnipotent (For an omnipotent being would be able to create a world where evil was not necessary.), or God is not omnibenevolent (Being able to use 'lesser' evils for 'greater' goods; this is not
omnibenevolence. At best, it is merely benevolence.). That, at its worst, completely renders claims to the absolute
moral goodness of God null and void.
Literally the only way to avoid the problem is to change the definitions. Either God's omnipotence is limited, somehow (This is actually an argument, that reality is such that smaller evils, such as pain and suffering, are necessary for greater goods, such as redemption, to occur. Problem there is that it puts something above God, namely reality, leading to the old 'if God loves good things because they are good, why do we bother with God?' thing.), which makes it no longer
omnipotence -- just really, really, potent potence -- or the goodness of God (Call it supreme appleness, if it pleases you.) is categorically different from the goodness of Man.
Basically, the only way to avoid contradiction is to either deny the
literal truth of biblical text (This is no great loss! Much great work involving faith, spirituality, and religion can still be done.) or abuse the language and change the meaning of things around so you can say one thing (God is Good) and mean another (God is.). I can't really blame the folks going the way of the second, though. While its a little shifty, it's easy to spot, and frankly put they're doing their best at an impossible task. The results of that infinitely fruitless work is very impressive, often very incredibly logical and well put together, it's just fundamentally flawed. When you base your starting foundation off contradiction, all things built from it will necessarily be tainted.