Was South's bidding really as "edgy" as an expert suggests?
Absolutely.

While the South hand has 11 HCP it should deduct one for the 4333 distribution. That's just a given. After that the spots are good but the Q is in the wrong suit - it will usually help the hand much more in Spades than in in Clubs. That's a wash so call it 10  Points even.

With this flat 10 and partner denying a 15-17 balanced hand or 4 spades with an upgrading distributional feature in the red suite, I am happy to pass 2S. To push twice more in hopes of finding partner with a magic 14 count is going to end up badly much more often than it will end well.