Io misspoke when he formulated the rhapsode's techne as the ability to know the sort of things any type of person should say. It is easy for Socrates to make Io admit that craftsmen of all other crafts will say things connected to their crafts more finely than a rhapsode could - this after all is what they have been assuming for a long time now.

Here I read through Platonic dialogues, translating and commenting on the Greek text as I go.

The resulting analyses may be found at:
https://theplatoparadigm.com

The full analyses include Euthyphro, Io, Hippias Minor, and Lysis, with extract/summaries from my books on Hippias Major, Meno, and Politeia (Republic)