The point is they're not stealing my identity from me, but from a third party. Why should I be on the hook for the consequences of someone else's negligence?

Really, they aren't stealing an identity at all, they are simply stealing information about you. Saying that someone stole your identity because they know non-secret information about you is about as sensible as saying that someone stole your body when they stole a picture of you. If a bank accepts someone showing a picture of you as proof that they are you, they are simply being an idiot.

Identity and the means to establish identity are the same thing as far as anyone is concerned in the current US model though

What about the term "identity theft" suggests that you should be on the hook?

The idea that there is a victim, and that's you. You had a bad thing done to you and are now the worse. In fact nothing was done to you -- some big stupid corporation gave money to a criminal is what happened. The big stupid corporation would prefer that this be seen as : you owe them the money because they thought the criminal was you.

The term suggests that you are the victim of the impersonation, when in fact the lender is the sole victim that should get hurt by that crime.

For you, the buck should stop (as is the case in much of EU) with saying "prove it was me - or you're not allowed to libel me by putting a bad mark on my credit and falsely claiming that I owe you money". At that point you're not the victim, it's not your problem, and the defrauded institution can choose to either take the losses and continue business as-is or perform their verification duty properly next time.

I kindof think that's a pointless question!? Even if that is an unjustified interpretation of the term, it still is an empirical fact that most people understand it that way and that corporations use this empirical fact in order to frame their failure as somebody else's.

If you want the public to understand that being impersonated is the fault of the person/institution being duped, it's probably not helpful to use a term that the public understands to mean that the person being impersonated is at fault, whether that interpretation is justified or not.

It's no different to intellectual property theft. It doesn't matter where it is taken from, but who the property belonged to and who was being deprived.