It's kind of different out here. Back in Detroit for interviews, I was normally put in front of a computer and asked to write code. Pretty practical, and I did well.
For whatever reason, out here everyone loves the whiteboard, run though a binary tree on a whiteboard, wtf does that have to do what what you are actually going to be doing? Nothing, but Google, Amazon and MS all have you do it, so everyone else copies it. Hard to put you on the spot like that over the phone.
Also your timing isn't the best, right before X-mas holidays.
PS Why doesn't slashdot like paragraphs?