There really are exceptionless rules, but we lose a lot focusing on rules to the exclusion of the corresponding virtues.

Consider two different acts:  Murdering and desecrating the body; murdering and eating the body.

Viewed simply as acts, it is not easy to say which is worse.  However, the latter shocks us more profoundly because it suggests a deeper disturbance of moral character.  That counts for something.

Related:

Commentary on Thomas Aquinas’s Virtue Ethics