I have a number of different thoughts on this...
The UEP does what is best for their business. These are largest producers in the United States. Most of their facilities are modern production systems that are a far cry from what the media portrays (filthy, unsanitary, abusive conditions). The facilities that the media highlights are typically smaller scale, regional operations working with older infrastructure under poor management. No matter how hard the UEP tries they can't convince the public that their facilities are are highly managed, sanitary production systems because there are always producers that taint the pool. By leveling the playing ground they can paint the entire U.S. egg industry in a different light, "This is how the entire U.S. egg industry does it because it is required by law".
But... Such laws will lead to further consolidation of the egg industry under the largest producers. The smaller producers with older infrastructure will be driven out allowing the the largest producers, with the deepest pockets, to pick up the slack.
For those concerned that this will affect backyard flocks, I wouldn't be too concerned. This law would make the "enriched cage" the minimum standard. Such laws generally only apply to commercial production at certain scales. For example, the FDA requires all flocks over 3000 hens in size to be registered with their department. All federal standards promulgated by the FDA, such as the new salmonella prevention regulations, only apply to those with flocks of over 3000 birds.