This post draws a helpful distinction between moral guidance and moral reaction. You look for moral guidance when you ask what you ought to do. You engage in moral reaction when you praise and blame.
Looking for moral guidance can be a separate enterprise from engaging in moral reaction if A’s doing x is wrong does not entail A is morally blameworthy if he does x. It seems plausible that this entailment doesn’t hold. Somebody is morally blameworthy if they act for condemnable reasons: to cause gratuitous pain or without regard to the potential harm caused to others, etc. But if somebody makes a moral mistake despite trying to do the right thing they don’t seem morally blameworthy — it would be harsh to condemn somebody for making their best efforts to do right.
If looking for moral guidance is a separate enterprise from engaging in moral reaction then you can look for moral guidance without committing yourself to a disposition to condemn whoever acts contrary to the moral guidance you accept. This, in turn, makes the whole enterprise of moral reasoning much more attractive. It means you can make a sincere effort to figure out what you ought to do without perpetually (and obnoxiously) standing in judgment of your fellows.