Nobody is saying hydrogen is free. Nor will the production of ammonia from compounds we have in abundance (i.e. water, air and rock) ever produce energy, as it's a high energy compound, releasing quite a bit of energy when combusted. But that is absolutely not what this is about.

However, I was refuting the GP's wrong assertion that the energy cost equation of this reaction shows that it cannot be a net energy producer.

It makes sense to optimize this step, because the energy equation shows the energy is just wasted as heat, as it's not contained in the compound itself.