Frankly, even a developer relations position can be a technical position. I personally think a developer relations person who does understand the inner workings of the code base he represents, or at least demonstrates the ability to understand it given time, will be much better at his job than someone who doesn't. So really, I agree with Google here in their decision.

There are a number of jobs at google that although do not involve writing code, are closely coupled with the technology google is working on - developer relations actually being a very good example. I think they are keeping the bar high in these instances for valid reasons. I'm sure there are positions where technical background is less crucial, graphic design comes to mind, but that's to be judged on a case by case basis. Everybody wants to work there, so they can demand very high standards, but in most instances i've heard about the standards are not incorrect, just high.

EDIT: And probably another reason is they simply want to keep the particular technical culture throughout the company.