> Yes, that's absolutely what it is. As a society, we seem to believe that information can be owned

Two wrongs (information cannot be "owned" in the same sense of a physical thing, regardless of how much one wants to be believe it; and that DRM can be effective) do not make one right. Note that I'm not discussing values here - just pure technical issues.

Here's the two problems of DRM in a nutshell, that make it into snake oil.

1. The "owner" of the content wants to make said content available to person X, but not to person X's recording device, which is indistinguishable from X.

2. It is enough for said content to be freed from DRM once, to become universally free of DRM.

No matter how smart your protocols, cryptography etc is, because (1) if you can display it on a screen, and take a picture of said screen, with a high resolution capture device, you've defeated DRM. And then because of (2) the DRM scheme, regardless of its other merits, becomes ineffective.

That's why DRM cannot be done right, even if you assume it's the right thing to do. (which I don't)

  > Plagiarism is an accusation which can ruin a career.

There's a difference between ownership of an idea, and plagiarism. An example of trying to 'own' an idea would be:

  1) Person A creates an idea
  2) Person B independently creates the same idea (or
     something extremely similar).
  3) Person A attempts to assert control over the idea
     by dictating what Person B can or cannot do with it
     based on the fact that Person A 'got there first.'

An example of plagiarism would be:

  1) Person A creates an idea.
  2) Person B copies Person A's idea, and attempts to claim
     independent creation (or attempts to claim creation prior
     to Person A).

The real difference is that with plagiarism, Person B is committing a fraud about the source of the idea. It's more about authorship than anything else. Even in a society where you couldn't own an idea, you could still have authorship as the first person to think of something.

Related: http://en.wikipedia.org/wiki/Moral_rights_(copyright_law)

There is a very important difference between "owning" information - which is impossible and any attempt to do so is morally reprehensible - and the "creator's right" of being named as said creator - which is perfectly fine. All your examples are more or less instances of the latter - it's not okay, for example, to plagiarize because you are violating everyone's right to truth.

"We have always felt entitled to do what we please with the fruit of our labors, and we feel no differently when that fruit is information."

Except that fruit of your labor is not "information", it's a "copy of information". And of course you are entitled to do whatever you want with it. As am I, if I have gained access to it by any means that did not violate your privacy (eg., breaking into your house or hacking into your computer) or other fundamental rights (copy"right" is not a right, it's a privilege - very, very important difference, as rights cannot be granted by law). In other words, I cannot force you to share something with me. But neither can you forbid me from sharing things I have - including pieces of information - unless they violate one of your fundamental rights (for example, your dignity).