Scratching the surface:

Democratically, the public enjoys participation in policy development through notice and comment rule-making, but not through this accession/acquiescence (which is politically motivated).

And legally, the public can (or can more-easily) challenge and seek invalidation of rule-making, but cannot (or cannot as easily) challenge effective policy choices made through litigation strategy in cases in which the agency is adverse to a single party, to the exclusion of non-parties and the public generally.

Of course it goes much deeper than this and there are many other differences and considerations.

In this instance, your view of the capital/labor outcomes is probably roughly true, and I agree in principle; but the same procedure could happen with opposite effects in a different administration and with contrary rules, for example.