NPS's offer to speak with him in private may just be an attempt to pacify him. If NPS really agrees with his reasoning, they could easily reword the contest rules, or promise to do so in the future.
What we need is more photographers speaking up, like Fairnsquare and many here. If we don't act to protect our rights ourselves, we can't expect others to.
I've also encountered the "speak to use in private" business. In one case regarding a contest run by a well-known photo blog the person who runs the site sent me an incredibly unprofessional (and borderline wacko) personal email for having dared to mention the contest terms in public. Basically I had quoted the terms in a blog post. When this person accused me of posting an error-filled article, I offered to correct any inaccuracies in my post... but the person (who will remain unnamed for now) never pointed any errors. (I noted later that this person and his associates did
change the terms of some of their following contests. :-)
I think that the "speak to me in private" request could be regarded as a partial success, but the follow-up steps must necessarily include the potential to speak publicly again. Essentially, the "speak in private" request demonstrates that there is a power in speaking of these things in public and that the sponsors both see the problem and fear that they would not look good in a public discussion.
If one is to have a "private conversation" about this with the sponsors, one needs to be very careful. I would certainly not agree that the outcome of the conversation should remain private, for example. I would certainly not agree to "discuss it in private and agree to keep it private."
The onerous rights-grabbing language used in many of the contests, if seen and understood by the public and the constituents of many of these groups, would damage their credibility. I'm thinking specifically of two run-ins I had. In one case I pointed out such a problem to the Sierra Club - a group that I have been a member of for decades - and I received two responses. One was an incredibly personal and angry attack. (I'm seeing a pattern here, by the way.) The other was a dismissive "we'd never do anything bad with the photos so why worry" response. (A second pattern.)
If the group would "never do anything bad with the photos," then they clearly should change the language of their contest terms so that their good intentions are clear. If they would never use the non-winning images of entrants, or let their affiliates use them, or use them without credit... and so forth... then there is no reason to include agreement terms that permit them to do those exact things and more.
(If you were signing a loan that permitted the party loaning the money to you to, oh, hold weekly parties at your home at your expense and give you no control over the guest list, assigned you all legal liability for anything that happened... and the other party said, "but, of course, we'd never actually do that!"... would you sign the loan papers? If no, why would would you agree to similar terms in a photo contest. If yes, please seek professional help! :-)