Why so much about sophists (in Plato)?

The sophists play a key role in Plato’s dialogues, and their attempt to stage what a true philosophical life would be, in the person of Socrates. The names of many of the dialogues, like the Gorgias, Hippias (Major and Minor), Euthydemus, and Protagaras, come from sophists. Then there is the dedicated dialogue, The Sophist, on this subject.

Other sophists or folk influenced by them, like Thrasymachus, play leading roles in other dialogues. Sophistry continues to be a foil against which true philosophy is defined, for instance in the central books of Plato’s…