Gonzalez Lodge, Commentary on Plato: Gorgias

ἀλλὰ λέγεις: this statement of Callicles may be meant in earnest, inasmuch as the previous words of Socrates are really somewhat confusing, although they are simply a paradoxical conclusion from Callicles' paradoxical propositions. But by confessing his inability to comprehend, Callicles gives Socrates the opportunity of supplying a proof of his previous exposition, and setting forth the principles upon which it rests. The distinction made in 497 e now becomes of value.

κακοὺς δὲ κακῶν: both the subj. as well as the subst. on which the gen. depends are to be supplied from the context. Note the chiasmus of the arrangement.

τὰ δὲ ἀγαθὰ κτἑ.: the preds. are τὰς ἡδονάς, τὰς ἀνίας, the art. defining a class. The art. with ἀγαθά refers back to ἀγαθῶν. We should also expect one with κακά.