That is not a fair question. How is the aggrieved party supposed to know they were friends in order to object at all? Run a background check? Most people show up in court expecting the Judge to be, at the very least, fair and impartial. Most people do not know the Judge, and he/she does not know them--that is how it should be.
Judge Klein, if he had any ethics at all, should have recused himself because he personally knew Judge McLean. He didn't.
Actually it's a perfectly fair question, because if the presiding judge had ANY kind of personal relationship with a party, he needs to disclose that up front in order to give the parties an opportunity to object. And in the real world, judges know a lot of people. That's how they get elected (or appointed). When I was on the bench it was the rare case when I didn't know one or more of the parties in one capacity or another. Can't be avoided and must be disclosed. And frankly there were any number of judges and former judges I would have been delighted to have had an opportunity to rule against!