{ 1 } - is a logical principle.
{ 2 } - tells us how we ought to live.

This claim says that moral judgments logically commit us to making similar evaluations about similar cases. If we violate this, then our moral judgments are inconsistent with each other.

This is a consistency rule. It isn't an imperative or moral judgment. It doesn't say "We ought to do such and such ..." Instead, it tell us what we must do if we're to be logically consistent in our moral beliefs.