Typical Chamber of Commerce tripe.
All pension agreements, whether made to union employees or not, are part of the agreement employers make with employees when figuring out compensation. Your pension is part of your pay. You earn it. But somewhere along the way, it became kosher for companies to say, "Sorry, we lied about what we were going to pay you. You're SOL."
Ironically, if one corporation did this to another corporation, it wouldn't be written off, the way pensions get waved away. It would wind up in court, and the promiser would be settling with the promisee.
No such luck for the little guy. Capitalism doesn't work that way.