That would be an example of a non-torturted metaphor. When you copy the famous quote verbatim and then substitute both parts of it for things that are almost entirely unrelated, it becomes tortured.

Is that right though? I feel like "tortured" is usually used more when one term is overly specific/over-fitted to the other. I've never heard it used like this, where it's about its provenance?

Not that anyone really cares here, but the gp quote isn't even really fundamentally a metaphor either way, its an exhortation to "imagine". The Orwell isn't even a metaphor!