He thinks it is pretty clear that these sequences have no major role in growth and development. "There has been a circular argument that if it's conserved it has activity."
Well, yes. The assumptions are those of Darwinian evolution.---> Things change. Things that are necessary for survival(activity) don't change(conserved).
There is no explanation for this under RMNS. Do you have one?
Not having an explanation is a rather common phenomenon in science. It is only a problem if you assume everything can be deduced from first principles. Otherwise it is merely a new challenge.