The problem is that the producer’s business model is based on making and selling copies. You’re not taking an original work, no, but you’re also not paying for the produced content.
Let’s expand the pig analogy.
A farmer has a sow and any piglets that it has are for sale. You steal a piglet. You haven’t stolen the original sow, but you have stolen the piglet you now have because you didn’t pay for it.
The problem is that the producer’s business model is based on making and selling copies. You’re not taking an original work, no, but you’re also not paying for the produced content.
Let’s expand the pig analogy.
A farmer has a sow and any piglets that it has are for sale. You steal a piglet. You haven’t stolen the original sow, but you have stolen the piglet you now have because you didn’t pay for it.
That analogy doesn’t work at all because the Sow produces a finite (and rather small at that) number of piglets over a given timespan.
It’s more akin to you getting a piglet/sow elsewhere. Now your piglet/sow need is satisfied and you won’t buy anything from this farmer.