We really don't. I hope you don't sincerely believe your fellow HNers are stupid enough to think that copying an artistic artifact somehow removes it from the possession of the original creator. We aren't and we don't. Which means this is just a matter of word choice. I can't think of much I'm less interested in reading than "You used this word in a way I don't agree with."
Besides, this usage of "theft" is not dissimilar from the already well established usage of "stole" as in "he stole my idea." If an idea can be stolen, it can certainly be theft to take the product of an idea, at least colloquially.
Of course it's a common usage, but that alone shouldn't make it acceptable usage. Lots of disparaging language is common usage. When you use a word with a certain intent, it's the usage of that word with that specific intent that should be questioned.
I think we should all be grownup enough to recognise that ideas can't really be stolen either. We also recognise the value of copying ideas. If we recognise these things, then we should use corresponding language to reflect our intent.
It is important to repeat "copying is not theft" because it's at the heart of the arguments that e.g. the MPAA make to the public in order to convince them of the evils of copyright infringement ("you wouldn't steal a car," etc). TFA seems to be trying to appeal to the evil of Kraft's deeds by suggesting that something has been stolen from him.
It seems clear to me that nothing of the sort of theft has happened, and at least some people would instead be flattered to have their work reproduced large scale instead of slinging accusations of theft. If it were me, I would use this to promote the value of my own work. Maybe I would try to talk to someone at Kraft before firing the lawyer cannons, perhaps just work out a deal where they give me some sort of recognition. Even recognising the copyright infringement, it seems to be on such small scale (one maze out of hundreds?) that it might be difficult to argue for damages incurred.
This person isn't flattered, but the language of "theft" indicates a graver damage than what actually has happened.
Honestly: I don't think the term "identity theft" is a good one. It's not clear at all what exactly that even means unless people have had it explained to them; and even then it's pretty vague and encompasses lots of things.
Identify theft is a kind of fraud or perhaps libel, but it's certainly not conventional theft.
Nevertheless, the term has taken on a life of its own, and that's just the way language works. The problem arises when people say inane things like "you wouldn't steal a car, would you?". That analogy is sort of like saying you shouldn't go on strike, after all, you wouldn't want somebody to strike you, right?
So, is it theft? Well, from a linguistic perspective: it's called whatever it's called. But it's simply deceptive to pretend that merely because the same word is used that the meaning must be equivalent too. It's particularly unfortunately that the manipulation of language is probably intentionally deceptive; the notion of intellectual property didn't arise amongst the average English speaker, but amongst a special interest group that stands to gain by causing this particular confusion.
If someone "steals" your identity, it isn't really theft sure. Really, you both have a pointer to that identity. The problem, which makes it a good idea for it to be illegal, is that you both have a pointer to the EXACT SAME identity. Thus, any destructive(or benevolent) changes they make affect your identity as well.
Contrast this with most forms of "copyright theft", where the original owner still has the original AND any changes you make to your copy have no effect on the original.
It was T.S. Eliot. and the real quote is "Immature poets imitate; mature poets steal; bad poets deface what they take, and good poets make it into something better, or at least something different."
Besides, this usage of "theft" is not dissimilar from the already well established usage of "stole" as in "he stole my idea." If an idea can be stolen, it can certainly be theft to take the product of an idea, at least colloquially.