Edgar publicly championed Curry as a cornerstone of his team (aka, virtually untouchable). In exchange for Curry and a 1st rounder, Edgar received Lamar Odom (mired in an absolutely dreadful year), a Kevin Garnett who was playing on the final year of his contract and rumored to be retiring, Metta World Peace (who hurts in about as many categories as he helps in), and a lottery pick in a draft headlined by Anthony Davis and a bunch of also-rans, according to most draftniks.
That was the way I saw it at the time. If Edgar had taken back some younger prospects instead of MWP or Odom and/or kept his own first, I might have felt better about the deal. At the time, it just made little sense to me.