word usage - How is "made FROM virgin [any material]" possible? Shouldn't it be "made OF virgin"?

What I know about 'made from' and 'made of' is this:

Chairs are made of wood - the wood is still wood, you see that AND
Paper is made from wood -wood disappears, you don't see wood

What I know about the word virgin as an adjective is this:

in its original pure or natural condition and not changed, touched or spoiled

So, keeping in mind that if *the original material is changed, it does not remain virgin. Said that, --[anything] made FROM virgin [anything] is not possible.

But here...

What makes it (they are talking about 3D printer filament) especially attractive is the cost of conventional filament made from virgin plastic: about $35 to $50 a kilogram.

The Guardian reads:

Extra-soft, quilted and multi-ply toilet roll made from virgin wood causes more damage than gas-guzzlers, fast food or McMansions, say campaigners

Question

Now, if we change/alter the original material, how is it possible to call it virgin? The moment you change/alter the main material, it's not virgin anymore! :)

So shouldn't we use 'made of virgin' (since it's not changed) over 'made from virgin' which means 'altered'.

Answer

"I married a virgin" doesn't mean she's a virgin anymore. The writers chose the word virgin to suggest that something pure, precious, and irreplaceable is being lost—wasted on an unworthy purpose.

When the newspaper article says that the toilet paper is made from virgin wood, it means the state of the wood before they manufactured the toilet paper. Virgin wood is the input to the manufacturing process. Toilet paper is the output. We do not call toilet paper "wood" at all, even though that's what it's made from. From virgin wood to toilet paper—from sacred purity to filthy impurity—that's how the writers are trying to get you to see the situation.

Made from is more correct here, since that phrase suggests that the material was transformed when the object was made, as wine is made from grapes. Made of suggests that the material is still recognizable in the completed object, like a bridge made of steel. There is no exact rule, of course.