Hipparchus a pretty well-known (pseudo?) Platonic dialogue, and this is not the first time I've seen it. The parent seems to suggest that the friend's distaste for greedy men is related to the situation of money supply at the time. For anyone familiar with the other Platonic dialogues and the history of 5th century Athens, it seems much more related to the timeless distaste of Socrates' young rich aristocratic friends for the nouveau riches traders and speculators of the time.