[*] 2316. With ἄν, it is implied that the obligation does (or did) not exist; without ἄν, it is implied that the action of the dependent infinitive is (or was) not realized. Thus the first sentence in 2315, without ἄν, would mean: if he were doing this (as he is not), one ought to blame him; but, as the case now stands, one does not blame him.
[*] 2316. With ἄν, it is implied that the obligation does (or did) not exist; without ἄν, it is implied that the action of the dependent infinitive is (or was) not realized. Thus the first sentence in 2315, without ἄν, would mean: if he were doing this (as he is not), one ought to blame him; but, as the case now stands, one does not blame him.