I think I see your point though; theft isn't defined by ownership, so ownership status is not a case for theft (although they do tend to be caused by the same things). "If the plane wasn't flying, then I didn't crash"; crashing is not defined by flight worthiness, or even being in the air.

The logic of the idiom is in the simile though, "buying ≠ owning" has the same logical flaw; there are lots of things we buy that can't be owned, chiefly services. Yet the expectation of the saying is that buying to own is not owning. Perhaps more explicit would be "If not giving what was payed for isn't stealing, then taking what should be given isn't stealing either", or "If you take our right to own, we'll take your right to own".

Like most sayings, being snappy is more useful that being correct, but there's also an important meaning there if we take the snap out of it.

[–] Katana314@lemmy.world 1 points 8 months ago

If someone invented a machine that could print out cars for cents on the dollar, that wouldn’t make stealing those cars fair; especially if inventing that machine cost him billions of dollars.

In fact that’s reasonably close to the case for certain kinds of food - the costs for producing them are infinitesimal, but the logistics of researching that development process, making storefronts, advertising them, and having staff on hand to process the purchase add up. Yet that doesn’t stop some people from pointing to that production cost as reason to shoplift.

Memes like this have always been backwards justification to excuse piracy.