Technically it was (Kingsfans.com super-villain) Pete D'Alessandro who had the GM job at the time but he'd only hired in 10 days before the draft so at best I think he only deserves partial blame. Chris Mullin (head of scouting I believe) and owner Vivek Ranadive probably had as much to do with that decision as he did.
In any case, CJ McCollum has obviously done quite well for himself and Ben McLemore is out of the league so obviously that was another huge miss for our revolving door of front office personnel. I do wish CJ would stop torching us over it though. It's been 10 years my guy!