Oh yeah? Tell that to United Airlines or General Motors...
I think in this case he's refering to the prohibition on ex post facto laws. The corporations took advantage of provisions of prevailing provisions in bankruptcy and pension law which don't apply in this case. The relevant point of law here is that legislatures can't retroactively make already earned benefits not dependent on good conduct or lack of criminal conviction under previously existing law subject to cancellation on the basis of a criminal conviction.