He's saying that a particular avenue of information gathering shouldn't be used at all. That's doing less! Elad is saying that all of those things (interviews,

He's saying that a particular avenue of information gathering shouldn't be used at all. That's doing less! Elad is saying that all of those things (interviews, hanging out, looking at shared code, etc etc) should be done and ALSO reference checks should be done. And of course the information from references can sometimes be vague and misleading. All information about candidates can be vague and misleading. It's the job of a good hiring manager to sort through all of this information and do they best that can to form a complete picture. The more information the better!